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112-504: Phosphorus is a chemical element ; it has symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus , but because it is highly reactive , phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about 0.1%, less abundant than hydrogen but more than manganese . In minerals, phosphorus generally occurs as phosphate . Elemental phosphorus

224-738: A pure element . In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the same atomic number, or number of protons . Nuclear scientists, however, define a pure element as one that consists of only one isotope. For example, a copper wire is 99.99% chemically pure if 99.99% of its atoms are copper, with 29 protons each. However it is not isotopically pure since ordinary copper consists of two stable isotopes, 69% Cu and 31% Cu, with different numbers of neutrons. However, pure gold would be both chemically and isotopically pure, since ordinary gold consists only of one isotope, Au. Atoms of chemically pure elements may bond to each other chemically in more than one way, allowing

336-431: A concentration in the Earth's crust of about one gram per kilogram (compare copper at about 0.06 grams). It is not found free in nature, but is widely distributed in many minerals , usually as phosphates. Inorganic phosphate rock , which is partially made of apatite (a group of minerals being, generally, pentacalcium triorthophosphate fluoride (hydroxide)), is today the chief commercial source of this element. According to

448-422: A conductor of electricity, and has puckered sheets of linked atoms. Another form, scarlet phosphorus, is obtained by allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight . When first isolated, it was observed that the green glow emanating from white phosphorus would persist for a time in a stoppered jar, but then cease. Robert Boyle in the 1680s ascribed it to "debilitation" of

560-540: A considerable amount of time. (See element naming controversy ). Precursors of such controversies involved the nationalistic namings of elements in the late 19th century. For example, lutetium was named in reference to Paris, France. The Germans were reluctant to relinquish naming rights to the French, often calling it cassiopeium . Similarly, the British discoverer of niobium originally named it columbium , in reference to

672-477: A different element in nuclear reactions , which change an atom's atomic number. Historically, the term "chemical element" meant a substance that cannot be broken down into constituent substances by chemical reactions, and for most practical purposes this definition still has validity. There was some controversy in the 1920s over whether isotopes deserved to be recognized as separate elements if they could be separated by chemical means. The term "(chemical) element"

784-424: A fertiliser in its pure form or part of being mixed with water in the form of sewage or sewage sludge . The most prevalent compounds of phosphorus are derivatives of phosphate (PO 4 ), a tetrahedral anion. Phosphate is the conjugate base of phosphoric acid, which is produced on a massive scale for use in fertilisers. Being triprotic, phosphoric acid converts stepwise to three conjugate bases: Phosphate exhibits

896-643: A few decay products, to have been differentiated from other elements. Most recently, the synthesis of element 118 (since named oganesson ) was reported in October 2006, and the synthesis of element 117 ( tennessine ) was reported in April 2010. Of these 118 elements, 94 occur naturally on Earth. Six of these occur in extreme trace quantities: technetium , atomic number 43; promethium , number 61; astatine , number 85; francium , number 87; neptunium , number 93; and plutonium , number 94. These 94 elements have been detected in

1008-525: A few elements, such as silver and gold , are found uncombined as relatively pure native element minerals . Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Air is mostly a mixture of molecular nitrogen and oxygen , though it does contain compounds including carbon dioxide and water , as well as atomic argon , a noble gas which is chemically inert and therefore does not undergo chemical reactions. The history of

1120-500: A pressure of 1 bar and a given temperature (typically at 298.15K). However, for phosphorus, the reference state is white phosphorus even though it is not the most stable allotrope, and the reference state for carbon is graphite, because the structure of graphite is more stable than that of the other allotropes. In thermochemistry , an element is defined to have an enthalpy of formation of zero in its reference state. Several kinds of descriptive categorizations can be applied broadly to

1232-483: A pressure of one atmosphere, are commonly used in characterizing the various elements. While known for most elements, either or both of these measurements is still undetermined for some of the radioactive elements available in only tiny quantities. Since helium remains a liquid even at absolute zero at atmospheric pressure, it has only a boiling point, and not a melting point, in conventional presentations. The density at selected standard temperature and pressure (STP)

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1344-511: A significant role. The effect of molecular mass can be partially isolated by comparing chemicals of similar structure (i.e. esters, alkanes, etc.). For instance, linear alkanes exhibit decreasing volatility as the number of carbons in the chain increases. Knowledge of volatility is often useful in the separation of components from a mixture. When a mixture of condensed substances contains multiple substances with different levels of volatility, its temperature and pressure can be manipulated such that

1456-430: A single step. Crude oil entering a refinery is composed of many useful chemicals that need to be separated. The crude oil flows into a distillation tower and is heated up, which allows the more volatile components such as butane and kerosene to vaporize. These vapors move up the tower and eventually come in contact with cold surfaces, which causes them to condense and be collected. The most volatile chemical condense at

1568-456: A small group, (the metalloids ), having intermediate properties and often behaving as semiconductors . A more refined classification is often shown in colored presentations of the periodic table. This system restricts the terms "metal" and "nonmetal" to only certain of the more broadly defined metals and nonmetals, adding additional terms for certain sets of the more broadly viewed metals and nonmetals. The version of this classification used in

1680-470: A source of P in routes to organophosphorus(III) compounds. For example, it is the precursor to triphenylphosphine : Treatment of phosphorus trihalides with alcohols and phenols gives phosphites, e.g. triphenylphosphite : Similar reactions occur for phosphorus oxychloride , affording triphenylphosphate : The name Phosphorus in Ancient Greece was the name for the planet Venus and is derived from

1792-457: A temperature where most of the ethanol vaporizes while most of the water remains liquid. The ethanol vapor is then collected and condensed in a separate container, resulting in a much more concentrated product. Volatility is an important consideration when crafting perfumes . Humans detect odors when aromatic vapors come in contact with receptors in the nose. Ingredients that vaporize quickly after being applied will produce fragrant vapors for

1904-431: A tendency to form chains and rings containing P-O-P bonds. Many polyphosphates are known, including ATP . Polyphosphates arise by dehydration of hydrogen phosphates such as HPO 4 and H 2 PO 4 . For example, the industrially important pentasodium triphosphate (also known as sodium tripolyphosphate , STPP) is produced industrially by the megatonne by this condensation reaction : Phosphorus pentoxide (P 4 O 10 )

2016-582: A transient intermediate in solution by thermolysis of organophosphorus precursor reagents. At still higher temperatures, P 2 dissociates into atomic P. Red phosphorus is polymeric in structure. It can be viewed as a derivative of P 4 wherein one P-P bond is broken, and one additional bond is formed with the neighbouring tetrahedron resulting in chains of P 21 molecules linked by van der Waals forces . Red phosphorus may be formed by heating white phosphorus to 250 °C (482 °F) or by exposing white phosphorus to sunlight. Phosphorus after this treatment

2128-576: A variant of the Michaelis-Arbuzov reaction with electrophiles, instead reverting to another phosphorus(III) compound through a sulfonium intermediate. These compounds generally feature P–P bonds. Examples include catenated derivatives of phosphine and organophosphines. Compounds containing P=P double bonds have also been observed, although they are rare. Phosphides arise by reaction of metals with red phosphorus. The alkali metals (group 1) and alkaline earth metals can form ionic compounds containing

2240-428: A white, waxy substance that glowed in the dark. Brand had discovered phosphorus. Specifically, Brand produced ammonium sodium hydrogen phosphate, (NH 4 )NaHPO 4 . While the quantities were essentially correct (it took about 1,100 litres [290 US gal] of urine to make about 60 g of phosphorus), it was unnecessary to allow the urine to rot first. Later scientists discovered that fresh urine yielded

2352-474: A whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than ~1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of

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2464-493: Is amorphous . Upon further heating, this material crystallises. In this sense, red phosphorus is not an allotrope, but rather an intermediate phase between the white and violet phosphorus, and most of its properties have a range of values. For example, freshly prepared, bright red phosphorus is highly reactive and ignites at about 300 °C (572 °F), though it is more stable than white phosphorus, which ignites at about 30 °C (86 °F). After prolonged heating or storage,

2576-451: Is isoelectronic with SF 6 . The most important oxyhalide is phosphorus oxychloride , (POCl 3 ), which is approximately tetrahedral. Before extensive computer calculations were feasible, it was thought that bonding in phosphorus(V) compounds involved d orbitals. Computer modeling of molecular orbital theory indicates that this bonding involves only s- and p-orbitals. All four symmetrical trihalides are well known: gaseous PF 3 ,

2688-404: Is 10 (for tin , element 50). The mass number of an element, A , is the number of nucleons (protons and neutrons) in the atomic nucleus. Different isotopes of a given element are distinguished by their mass number, which is written as a superscript on the left hand side of the chemical symbol (e.g., U). The mass number is always an integer and has units of "nucleons". Thus, magnesium-24 (24

2800-606: Is a mixture of C (about 98.9%), C (about 1.1%) and about 1 atom per trillion of C. Most (54 of 94) naturally occurring elements have more than one stable isotope. Except for the isotopes of hydrogen (which differ greatly from each other in relative mass—enough to cause chemical effects), the isotopes of a given element are chemically nearly indistinguishable. All elements have radioactive isotopes (radioisotopes); most of these radioisotopes do not occur naturally. Radioisotopes typically decay into other elements via alpha decay , beta decay , or inverse beta decay ; some isotopes of

2912-435: Is a colourless gas and the molecules have trigonal bipyramidal geometry. PCl 5 is a colourless solid which has an ionic formulation of PCl 4 PCl 6 , but adopts the trigonal bipyramidal geometry when molten or in the vapour phase. PBr 5 is an unstable solid formulated as PBr 4 Brand PI 5 is not known. The pentachloride and pentafluoride are Lewis acids . With fluoride, PF 5 forms PF 6 , an anion that

3024-406: Is a dimensionless number equal to the atomic mass divided by the atomic mass constant , which equals 1 Da. In general, the mass number of a given nuclide differs in value slightly from its relative atomic mass, since the mass of each proton and neutron is not exactly 1 Da; since the electrons contribute a lesser share to the atomic mass as neutron number exceeds proton number; and because of

3136-406: Is a measurement of how readily a condensed phase forms a vapor at a given temperature. A substance enclosed in a sealed vessel initially at vacuum (no air inside) will quickly fill any empty space with vapor. After the system reaches equilibrium and the rate of evaporation matches the rate of condensation, the vapor pressure can be measured. Increasing the temperature increases the amount of vapor that

3248-456: Is a naturally occurring metal-rich phosphide found in meteorites. The structures of the metal-rich and phosphorus-rich phosphides can be complex. Phosphine (PH 3 ) and its organic derivatives (PR 3 ) are structural analogues of ammonia (NH 3 ), but the bond angles at phosphorus are closer to 90° for phosphine and its organic derivatives. Phosphine is an ill-smelling, toxic gas. Phosphorus has an oxidation number of −3 in phosphine. Phosphine

3360-402: Is aged or otherwise impure (e.g., weapons-grade, not lab-grade WP) is also called yellow phosphorus. White phosphorus is highly flammable and pyrophoric (self-igniting) in air; it faintly glows green and blue in the dark when exposed to oxygen. The autoxidation commonly coats samples with white phosphorus pentoxide ( P 4 O 10 ): P 4 tetrahedra, but with oxygen inserted between

3472-547: Is also required. Shielding requires special consideration. The high energy of the beta particles gives rise to secondary emission of X-rays via Bremsstrahlung (braking radiation) in dense shielding materials such as lead. Therefore, the radiation must be shielded with low density materials such as acrylic or other plastic, water, or (when transparency is not required), even wood. In 2013, astronomers detected phosphorus in Cassiopeia ;A , which confirmed that this element

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3584-812: Is an ongoing area of scientific study. The lightest elements are hydrogen and helium , both created by Big Bang nucleosynthesis in the first 20 minutes of the universe in a ratio of around 3:1 by mass (or 12:1 by number of atoms), along with tiny traces of the next two elements, lithium and beryllium . Almost all other elements found in nature were made by various natural methods of nucleosynthesis . On Earth, small amounts of new atoms are naturally produced in nucleogenic reactions, or in cosmogenic processes, such as cosmic ray spallation . New atoms are also naturally produced on Earth as radiogenic daughter isotopes of ongoing radioactive decay processes such as alpha decay , beta decay , spontaneous fission , cluster decay , and other rarer modes of decay. Of

3696-460: Is based on a Latin or other traditional word, for example adopting "gold" rather than "aurum" as the name for the 79th element (Au). IUPAC prefers the British spellings " aluminium " and "caesium" over the U.S. spellings "aluminum" and "cesium", and the U.S. "sulfur" over British "sulphur". However, elements that are practical to sell in bulk in many countries often still have locally used national names, and countries whose national language does not use

3808-552: Is considered unstable, but is a product of crystalline phosphorus nitride decomposition at 1100 K. Similarly, H 2 PN is considered unstable, and phosphorus nitride halogens like F 2 PN, Cl 2 PN, Br 2 PN, and I 2 PN oligomerise into cyclic polyphosphazenes . For example, compounds of the formula (PNCl 2 ) n exist mainly as rings such as the trimer hexachlorophosphazene . The phosphazenes arise by treatment of phosphorus pentachloride with ammonium chloride: PCl 5 + NH 4 Cl → 1/ n (NPCl 2 ) n + 4 HCl When

3920-445: Is formed and thus the vapor pressure. In a mixture, each substance contributes to the overall vapor pressure of the mixture, with more volatile compounds making a larger contribution. Boiling point is the temperature at which the vapor pressure of a liquid is equal to the surrounding pressure, causing the liquid to rapidly evaporate, or boil. It is closely related to vapor pressure, but is dependent on pressure. The normal boiling point

4032-421: Is often described using vapor pressures or boiling points (for liquids). High vapor pressures indicate a high volatility, while high boiling points indicate low volatility. Vapor pressures and boiling points are often presented in tables and charts that can be used to compare chemicals of interest. Volatility data is typically found through experimentation over a range of temperatures and pressures. Vapor pressure

4144-436: Is often used in characterizing the elements. Density is often expressed in grams per cubic centimetre (g/cm ). Since several elements are gases at commonly encountered temperatures, their densities are usually stated for their gaseous forms; when liquefied or solidified, the gaseous elements have densities similar to those of the other elements. When an element has allotropes with different densities, one representative allotrope

4256-856: Is produced by hydrolysis of calcium phosphide , Ca 3 P 2 . Unlike ammonia, phosphine is oxidised by air. Phosphine is also far less basic than ammonia. Other phosphines are known which contain chains of up to nine phosphorus atoms and have the formula P n H n +2 . The highly flammable gas diphosphine (P 2 H 4 ) is an analogue of hydrazine . Phosphorus oxoacids are extensive, often commercially important, and sometimes structurally complicated. They all have acidic protons bound to oxygen atoms, some have nonacidic protons that are bonded directly to phosphorus and some contain phosphorus–phosphorus bonds. Although many oxoacids of phosphorus are formed, only nine are commercially important, and three of them, hypophosphorous acid , phosphorous acid , and phosphoric acid , are particularly important. The PN molecule

4368-483: Is produced in supernovae as a byproduct of supernova nucleosynthesis . The phosphorus-to- iron ratio in material from the supernova remnant could be up to 100 times higher than in the Milky Way in general. In 2020, astronomers analysed ALMA and ROSINA data from the massive star-forming region AFGL 5142, to detect phosphorus-bearing molecules and how they are carried in comets to the early Earth. Phosphorus has

4480-492: Is readily incorporated into bone and nucleic acids . For these reasons, Occupational Safety and Health Administration in the United States, and similar institutions in other developed countries require personnel working with P to wear lab coats, disposable gloves, and safety glasses or goggles to protect the eyes, and avoid working directly over open containers. Monitoring personal, clothing, and surface contamination

4592-468: Is stable and is therefore present at 100% abundance. The half-integer nuclear spin and high abundance of P make phosphorus-31 NMR spectroscopy a very useful analytical tool in studies of phosphorus-containing samples. Two radioactive isotopes of phosphorus have half-lives suitable for biological scientific experiments. These are: The high-energy beta particles from P penetrate skin and corneas and any P ingested, inhaled, or absorbed

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4704-507: Is the acid anhydride of phosphoric acid, but several intermediates between the two are known. This waxy white solid reacts vigorously with water. With metal cations , phosphate forms a variety of salts. These solids are polymeric, featuring P-O-M linkages. When the metal cation has a charge of 2+ or 3+, the salts are generally insoluble, hence they exist as common minerals. Many phosphate salts are derived from hydrogen phosphate (HPO 4 ). PCl 5 and PF 5 are common compounds. PF 5

4816-416: Is the anhydride of P(OH) 3 , the minor tautomer of phosphorous acid. The structure of P 4 O 6 is like that of P 4 O 10 without the terminal oxide groups. Symmetric phosphorus(III) trithioesters (e.g. P(SMe) 3 ) can be produced from the reaction of white phosphorus and the corresponding disulfide , or phosphorus(III) halides and thiolates . Unlike the corresponding esters, they do not undergo

4928-452: Is the boiling point at atmospheric pressure, but it can also be reported at higher and lower pressures. An important factor influencing a substance's volatility is the strength of the interactions between its molecules. Attractive forces between molecules are what holds materials together, and materials with stronger intermolecular forces , such as most solids, are typically not very volatile. Ethanol and dimethyl ether , two chemicals with

5040-523: Is the electrons are highly delocalized . This has been illustrated by calculations of the magnetically induced currents, which sum up to 29 nA/T, much more than in the archetypical aromatic molecule benzene (11 nA/T). White phosphorus exists in two crystalline forms: α (alpha) and β (beta). At room temperature, the α-form is stable. It is more common, has cubic crystal structure and at 195.2 K (−78.0 °C), it transforms into β-form, which has hexagonal crystal structure. These forms differ in terms of

5152-509: Is the least reactive allotrope and the thermodynamically stable form below 550 °C (1,022 °F). It is also known as β-metallic phosphorus and has a structure somewhat resembling that of graphite . It is obtained by heating white phosphorus under high pressures (about 12,000 standard atmospheres or 1.2 gigapascals). It can also be produced at ambient conditions using metal salts, e.g. mercury, as catalysts. In appearance, properties, and structure, it resembles graphite , being black and flaky,

5264-426: Is the mass number) is an atom with 24 nucleons (12 protons and 12 neutrons). Whereas the mass number simply counts the total number of neutrons and protons and is thus an integer, the atomic mass of a particular isotope (or "nuclide") of the element is the mass of a single atom of that isotope, and is typically expressed in daltons (symbol: Da), or universal atomic mass units (symbol: u). Its relative atomic mass

5376-532: Is typically selected in summary presentations, while densities for each allotrope can be stated where more detail is provided. For example, the three familiar allotropes of carbon ( amorphous carbon , graphite , and diamond ) have densities of 1.8–2.1, 2.267, and 3.515 g/cm , respectively. The elements studied to date as solid samples have eight kinds of crystal structures : cubic , body-centered cubic , face-centered cubic, hexagonal , monoclinic , orthorhombic , rhombohedral , and tetragonal . For some of

5488-417: Is used in two different but closely related meanings: it can mean a chemical substance consisting of a single kind of atoms, or it can mean that kind of atoms as a component of various chemical substances. For example, molecules of water (H 2 O) contain atoms of hydrogen (H) and oxygen (O), so water can be said as a compound consisting of the elements hydrogen (H) and oxygen (O) even though it does not contain

5600-429: Is very strong; fullerenes , which have nearly spherical shapes; and carbon nanotubes , which are tubes with a hexagonal structure (even these may differ from each other in electrical properties). The ability of an element to exist in one of many structural forms is known as 'allotropy'. The reference state of an element is defined by convention, usually as the thermodynamically most stable allotrope and physical state at

5712-585: Is widely used. For example, the French chemical terminology distinguishes élément chimique (kind of atoms) and corps simple (chemical substance consisting of a single kind of atoms); the Russian chemical terminology distinguishes химический элемент and простое вещество . Almost all baryonic matter in the universe is composed of elements (among rare exceptions are neutron stars ). When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds . Only

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5824-523: The Greek words (φῶς = light, φέρω = carry), which roughly translates as light-bringer or light carrier. (In Greek mythology and tradition, Augerinus (Αυγερινός = morning star, still in use today), Hesperus or Hesperinus (΄Εσπερος or Εσπερινός or Αποσπερίτης = evening star, still in use today) and Eosphorus (Εωσφόρος = dawnbearer, not in use for the planet after Christianity) are close homologues, and also associated with Phosphorus-the-morning-star ). According to

5936-480: The International Union of Pure and Applied Chemistry (IUPAC) had recognized a total of 118 elements. The first 94 occur naturally on Earth , and the remaining 24 are synthetic elements produced in nuclear reactions. Save for unstable radioactive elements (radioelements) which decay quickly, nearly all elements are available industrially in varying amounts. The discovery and synthesis of further new elements

6048-625: The Latin alphabet are likely to use the IUPAC element names. According to IUPAC, element names are not proper nouns; therefore, the full name of an element is not capitalized in English, even if derived from a proper noun , as in californium and einsteinium . Isotope names are also uncapitalized if written out, e.g., carbon-12 or uranium-235 . Chemical element symbols (such as Cf for californium and Es for einsteinium), are always capitalized (see below). In

6160-646: The New World . It was used extensively as such by American publications before the international standardization (in 1950). Before chemistry became a science , alchemists designed arcane symbols for both metals and common compounds. These were however used as abbreviations in diagrams or procedures; there was no concept of atoms combining to form molecules . With his advances in the atomic theory of matter, John Dalton devised his own simpler symbols, based on circles, to depict molecules. Volatility (chemistry) Volatility itself has no defined numerical value, but it

6272-658: The US Geological Survey (USGS) , about 50 percent of the global phosphorus reserves are in Amazigh nations like Morocco , Algeria and Tunisia . 85% of Earth's known reserves are in Morocco with smaller deposits in China , Russia , Florida , Idaho , Tennessee , Utah , and elsewhere. Albright and Wilson in the UK and their Niagara Falls plant, for instance, were using phosphate rock in

6384-423: The kinetic isotope effect is significant). Thus, all carbon isotopes have nearly identical chemical properties because they all have six electrons, even though they may have 6 to 8 neutrons. That is why atomic number, rather than mass number or atomic weight , is considered the identifying characteristic of an element. The symbol for atomic number is Z . Isotopes are atoms of the same element (that is, with

6496-405: The nuclear binding energy and electron binding energy. For example, the atomic mass of chlorine-35 to five significant digits is 34.969 Da and that of chlorine-37 is 36.966 Da. However, the relative atomic mass of each isotope is quite close to its mass number (always within 1%). The only isotope whose atomic mass is exactly a natural number is C, which has a mass of 12 Da; because

6608-417: The phosphide ion, P. These compounds react with water to form phosphine . Other phosphides , for example Na 3 P 7 , are known for these reactive metals. With the transition metals as well as the monophosphides there are metal-rich phosphides, which are generally hard refractory compounds with a metallic lustre, and phosphorus-rich phosphides which are less stable and include semiconductors. Schreibersite

6720-555: The 1890s and 1900s from Tennessee, Florida, and the Îles du Connétable ( guano island sources of phosphate); by 1950, they were using phosphate rock mainly from Tennessee and North Africa. Organic sources, namely urine , bone ash and (in the latter 19th century) guano , were historically of importance but had only limited commercial success. As urine contains phosphorus, it has fertilising qualities which are still harnessed today in some countries, including Sweden , using methods for reuse of excreta . To this end, urine can be used as

6832-638: The 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope (except for technetium , element 43 and promethium , element 61, which have no stable isotopes). Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected. Some of these elements, notably bismuth (atomic number 83), thorium (atomic number 90), and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of

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6944-487: The French, Italians, Greeks, Portuguese and Poles prefer "azote/azot/azoto" (from roots meaning "no life") for "nitrogen". For purposes of international communication and trade, the official names of the chemical elements both ancient and more recently recognized are decided by the International Union of Pure and Applied Chemistry (IUPAC), which has decided on a sort of international English language, drawing on traditional English names even when an element's chemical symbol

7056-495: The Oxford English Dictionary, the correct spelling of the element is phosphorus . The word phosphorous is the adjectival form of the P valence: so, just as sulfur forms sulfurous and sulfuric compounds, phosphorus forms phosphorous compounds (e.g., phosphorous acid ) and P valence phosphoric compounds (e.g., phosphoric acids and phosphates ). The discovery of phosphorus, the first element to be discovered that

7168-459: The aid of his assistant, Ambrose Godfrey-Hanckwitz . Godfrey later made a business of the manufacture of phosphorus. Boyle states that Kraft gave him no information as to the preparation of phosphorus other than that it was derived from "somewhat that belonged to the body of man". This gave Boyle a valuable clue, so that he, too, managed to make phosphorus, and published the method of its manufacture. Later he improved Brand's process by using sand in

7280-423: The air. In fact, this process is caused by the phosphorus reacting with oxygen in the air; in a sealed container, this process will eventually stop when all the oxygen in the container is consumed. By the 18th century, it was known that in pure oxygen, phosphorus does not glow at all; there is only a range of partial pressures at which it does. Heat can be applied to drive the reaction at higher pressures. In 1974,

7392-487: The atomic masses of the elements (their atomic weights or atomic masses) do not always increase monotonically with their atomic numbers. The naming of various substances now known as elements precedes the atomic theory of matter, as names were given locally by various cultures to various minerals, metals, compounds, alloys, mixtures, and other materials, though at the time it was not known which chemicals were elements and which compounds. As they were identified as elements,

7504-413: The chemical substances (di)hydrogen (H 2 ) and (di)oxygen (O 2 ), as H 2 O molecules are different from H 2 and O 2 molecules. For the meaning "chemical substance consisting of a single kind of atoms", the terms "elementary substance" and "simple substance" have been suggested, but they have not gained much acceptance in English chemical literature, whereas in some other languages their equivalent

7616-635: The chloride groups are replaced by alkoxide (RO), a family of polymers is produced with potentially useful properties. Phosphorus forms a wide range of sulfides, where the phosphorus can be in P(V), P(III) or other oxidation states. The three-fold symmetric P 4 S 3 is used in strike-anywhere matches. P 4 S 10 and P 4 O 10 have analogous structures. Mixed oxyhalides and oxyhydrides of phosphorus(III) are almost unknown. Compounds with P-C and P-O-C bonds are often classified as organophosphorus compounds. They are widely used commercially. The PCl 3 serves as

7728-489: The color darkens (see infobox images); the resulting product is more stable and does not spontaneously ignite in air. Violet phosphorus is a form of phosphorus that can be produced by day-long annealing of red phosphorus above 550 °C. In 1865, Hittorf discovered that when phosphorus was recrystallised from molten lead , a red/purple form is obtained. Therefore, this form is sometimes known as "Hittorf's phosphorus" (or violet or α-metallic phosphorus). Black phosphorus

7840-408: The dalton is defined as 1/12 of the mass of a free neutral carbon-12 atom in the ground state. The standard atomic weight (commonly called "atomic weight") of an element is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance, relative to the atomic mass unit. This number may be a fraction that is not close to

7952-410: The dark without burning. Although the term phosphorescence is derived from phosphorus, the reaction that gives phosphorus its glow is properly called chemiluminescence (glowing due to a cold chemical reaction), not phosphorescence (re-emitting light that previously fell onto a substance and excited it). There are 22 known isotopes of phosphorus, ranging from P to P . Only P

8064-416: The discovery and use of elements began with early human societies that discovered native minerals like carbon , sulfur , copper and gold (though the modern concept of an element was not yet understood). Attempts to classify materials such as these resulted in the concepts of classical elements , alchemy , and similar theories throughout history. Much of the modern understanding of elements developed from

8176-526: The element. Two or more atoms can combine to form molecules . Some elements are formed from molecules of identical atoms , e. g. atoms of hydrogen (H) form diatomic molecules (H 2 ). Chemical compounds are substances made of atoms of different elements; they can have molecular or non-molecular structure. Mixtures are materials containing different chemical substances; that means (in case of molecular substances) that they contain different types of molecules. Atoms of one element can be transformed into atoms of

8288-406: The elements are available by name, atomic number, density, melting point, boiling point and chemical symbol , as well as ionization energy . The nuclides of stable and radioactive elements are also available as a list of nuclides , sorted by length of half-life for those that are unstable. One of the most convenient, and certainly the most traditional presentation of the elements, is in the form of

8400-470: The elements are often summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ( "periods" ) in which the columns ( "groups" ) share recurring ("periodic") physical and chemical properties. The table contains 118 confirmed elements as of 2021. Although earlier precursors to this presentation exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869, who intended

8512-480: The elements can be uniquely sequenced by atomic number, conventionally from lowest to highest (as in a periodic table), sets of elements are sometimes specified by such notation as "through", "beyond", or "from ... through", as in "through iron", "beyond uranium", or "from lanthanum through lutetium". The terms "light" and "heavy" are sometimes also used informally to indicate relative atomic numbers (not densities), as in "lighter than carbon" or "heavier than lead", though

8624-413: The elements without any stable isotopes are technetium (atomic number 43), promethium (atomic number 61), and all observed elements with atomic number greater than 82. Of the 80 elements with at least one stable isotope, 26 have only one stable isotope. The mean number of stable isotopes for the 80 stable elements is 3.1 stable isotopes per element. The largest number of stable isotopes for a single element

8736-474: The elements, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystal structures as solids, and their origins. Several terms are commonly used to characterize the general physical and chemical properties of the chemical elements. A first distinction is between metals , which readily conduct electricity , nonmetals , which do not, and

8848-492: The existing names for anciently known elements (e.g., gold, mercury, iron) were kept in most countries. National differences emerged over the element names either for convenience, linguistic niceties, or nationalism. For example, German speakers use "Wasserstoff" (water substance) for "hydrogen", "Sauerstoff" (acid substance) for "oxygen" and "Stickstoff" (smothering substance) for "nitrogen"; English and some other languages use "sodium" for "natrium", and "potassium" for "kalium"; and

8960-630: The explosive stellar nucleosynthesis that produced the heavy metals before the formation of our Solar System . At over 1.9 × 10 years, over a billion times longer than the estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any isotope, and is almost always considered on par with the 80 stable elements. The heaviest elements (those beyond plutonium, element 94) undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized . There are now 118 known elements. In this context, "known" means observed well enough, even from just

9072-529: The formation of Earth, they are certain to have completely decayed, and if present in novae, are in quantities too small to have been noted. Technetium was the first purportedly non-naturally occurring element synthesized, in 1937, though trace amounts of technetium have since been found in nature (and also the element may have been discovered naturally in 1925). This pattern of artificial production and later natural discovery has been repeated with several other radioactive naturally occurring rare elements. List of

9184-521: The glow was explained by R. J. van Zee and A. U. Khan. A reaction with oxygen takes place at the surface of the solid (or liquid) phosphorus, forming the short-lived molecules HPO and P 2 O 2 that both emit visible light. The reaction is slow and only very little of the intermediates are required to produce the luminescence, hence the extended time the glow continues in a stoppered jar. Since its discovery, phosphors and phosphorescence were used loosely to describe substances that shine in

9296-431: The half-lives predicted for the observationally stable lead isotopes range from 10 to 10 years. Elements with atomic numbers 43, 61, and 83 through 94 are unstable enough that their radioactive decay can be detected. Three of these elements, bismuth (element 83), thorium (90), and uranium (92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced

9408-399: The heaviest elements also undergo spontaneous fission . Isotopes that are not radioactive, are termed "stable" isotopes. All known stable isotopes occur naturally (see primordial nuclide ). The many radioisotopes that are not found in nature have been characterized after being artificially produced. Certain elements have no stable isotopes and are composed only of radioisotopes: specifically

9520-543: The heavy elements before the formation of the Solar System. For example, at over 1.9 × 10 years, over a billion times longer than the estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any isotope. The last 24 elements (those beyond plutonium, element 94) undergo radioactive decay with short half-lives and cannot be produced as daughters of longer-lived elements, and thus are not known to occur in nature at all. 1 The properties of

9632-445: The more volatile components change to a vapor while the less volatile substances remain in the liquid or solid phase. The newly formed vapor can then be discarded or condensed into a separate container. When the vapors are collected, this process is known as distillation . The process of petroleum refinement utilizes a technique known as fractional distillation , which allows several chemicals of varying volatility to be separated in

9744-487: The most important allotrope is white phosphorus , often abbreviated WP. White phosphorus is a soft, waxy molecular solid composed of P 4 tetrahedra . This P 4 tetrahedron is also present in liquid and gaseous phosphorus up to the temperature of 800 °C (1,500 °F; 1,100 K) when it starts decomposing to P 2 molecules. The nature of bonding in this P 4 tetrahedron can be described by spherical aromaticity or cluster bonding, that

9856-418: The periodic table, which groups together elements with similar chemical properties (and usually also similar electronic structures). The atomic number of an element is equal to the number of protons in each atom, and defines the element. For example, all carbon atoms contain 6 protons in their atomic nucleus ; so the atomic number of carbon is 6. Carbon atoms may have different numbers of neutrons; atoms of

9968-426: The periodic tables presented here includes: actinides , alkali metals , alkaline earth metals , halogens , lanthanides , transition metals , post-transition metals , metalloids , reactive nonmetals , and noble gases . In this system, the alkali metals, alkaline earth metals, and transition metals, as well as the lanthanides and the actinides, are special groups of the metals viewed in a broader sense. Similarly,

10080-436: The phosphorus atoms and at the vertices. White phosphorus is a napalm additive, and the characteristic odour of combustion is garlicky. White phosphorus is insoluble in water but soluble in carbon disulfide. Thermal decomposition of P 4 at 1100 K gives diphosphorus , P 2 . This species is not stable as a solid or liquid. The dimeric unit contains a triple bond and is analogous to N 2 . It can also be generated as

10192-435: The phosphorus that plants remove from the soil, and its annual demand is rising nearly twice as fast as the growth of the human population. Other applications include organophosphorus compounds in detergents , pesticides , and nerve agents . Phosphorus has several allotropes that exhibit strikingly diverse properties. The two most common allotropes are white phosphorus and red phosphorus. For both pure and applied uses,

10304-433: The process produced a white material that glowed in the dark and burned brilliantly. It was named phosphorus mirabilis ("miraculous bearer of light"). Brand's process originally involved letting urine stand for days until it gave off a terrible stench. Then he boiled it down to a paste, heated this paste to a high temperature, and led the vapours through water, where he hoped they would condense to gold. Instead, he obtained

10416-412: The pure element to exist in multiple chemical structures ( spatial arrangements of atoms ), known as allotropes , which differ in their properties. For example, carbon can be found as diamond , which has a tetrahedral structure around each carbon atom; graphite , which has layers of carbon atoms with a hexagonal structure stacked on top of each other; graphene , which is a single layer of graphite that

10528-457: The reaction (still using urine as base material), Chemical element A chemical element is a chemical substance whose atoms all have the same number of protons . The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus. Atoms of the same element can have different numbers of neutrons in their nuclei, known as isotopes of

10640-772: The reactive nonmetals and the noble gases are nonmetals viewed in the broader sense. In some presentations, the halogens are not distinguished, with astatine identified as a metalloid and the others identified as nonmetals. Another commonly used basic distinction among the elements is their state of matter (phase), whether solid , liquid , or gas , at standard temperature and pressure (STP). Most elements are solids at STP, while several are gases. Only bromine and mercury are liquid at 0 degrees Celsius (32 degrees Fahrenheit) and 1 atmosphere pressure; caesium and gallium are solid at that temperature, but melt at 28.4°C (83.2°F) and 29.8°C (85.6°F), respectively. Melting and boiling points , typically expressed in degrees Celsius at

10752-425: The relative orientations of the constituent P 4 tetrahedra. White phosphorus is the least stable, the most reactive, the most volatile , the least dense and the most toxic of the allotropes. White phosphorus gradually changes to red phosphorus, accelerated by light and heat. Samples of white phosphorus almost always contain some red phosphorus and accordingly appear yellow. For this reason, white phosphorus that

10864-919: The remaining 11 elements have half lives too short for them to have been present at the beginning of the Solar System, and are therefore considered transient elements. Of these 11 transient elements, five ( polonium , radon , radium , actinium , and protactinium ) are relatively common decay products of thorium and uranium . The remaining six transient elements (technetium, promethium, astatine, francium , neptunium , and plutonium ) occur only rarely, as products of rare decay modes or nuclear reaction processes involving uranium or other heavy elements. Elements with atomic numbers 1 through 82, except 43 (technetium) and 61 (promethium), each have at least one isotope for which no radioactive decay has been observed. Observationally stable isotopes of some elements (such as tungsten and lead ), however, are predicted to be slightly radioactive with very long half-lives: for example,

10976-573: The same amount of phosphorus. Brand at first tried to keep the method secret, but later sold the recipe for 200 thalers to Johann Daniel Kraft ( de ) from Dresden. Kraft toured much of Europe with it, including England, where he met with Robert Boyle . The secret—that the substance was made from urine—leaked out, and Johann Kunckel (1630–1703) was able to reproduce it in Sweden (1678). Later, Boyle in London (1680) also managed to make phosphorus, possibly with

11088-495: The same element having different numbers of neutrons are known as isotopes of the element. The number of protons in the nucleus also determines its electric charge , which in turn determines the number of electrons of the atom in its non-ionized state. The electrons are placed into atomic orbitals that determine the atom's chemical properties . The number of neutrons in a nucleus usually has very little effect on an element's chemical properties; except for hydrogen (for which

11200-585: The same formula (C 2 H 6 O), have different volatilities due to the different interactions that occur between their molecules in the liquid phase: ethanol molecules are capable of hydrogen bonding while dimethyl ether molecules are not. The result in an overall stronger attractive force between the ethanol molecules, making it the less volatile substance of the two. In general, volatility tends to decrease with increasing molecular mass because larger molecules can participate in more intermolecular bonding, although other factors such as structure and polarity play

11312-404: The same number of protons in their nucleus), but having different numbers of neutrons . Thus, for example, there are three main isotopes of carbon. All carbon atoms have 6 protons, but they can have either 6, 7, or 8 neutrons. Since the mass numbers of these are 12, 13 and 14 respectively, said three isotopes are known as carbon-12 , carbon-13 , and carbon-14 ( C, C, and C). Natural carbon

11424-457: The second half of the 20th century, physics laboratories became able to produce elements with half-lives too short for an appreciable amount of them to exist at any time. These are also named by IUPAC, which generally adopts the name chosen by the discoverer. This practice can lead to the controversial question of which research group actually discovered an element, a question that delayed the naming of elements with atomic number of 104 and higher for

11536-496: The synthetically produced transuranic elements, available samples have been too small to determine crystal structures. Chemical elements may also be categorized by their origin on Earth, with the first 94 considered naturally occurring, while those with atomic numbers beyond 94 have only been produced artificially via human-made nuclear reactions. Of the 94 naturally occurring elements, 83 are considered primordial and either stable or weakly radioactive. The longest-lived isotopes of

11648-955: The table to illustrate recurring trends in the properties of the elements. The layout of the table has been refined and extended over time as new elements have been discovered and new theoretical models have been developed to explain chemical behavior. Use of the periodic table is now ubiquitous in chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics , geology , biology , materials science , engineering , agriculture , medicine , nutrition , environmental health , and astronomy . Its principles are especially important in chemical engineering . The various chemical elements are formally identified by their unique atomic numbers, their accepted names, and their chemical symbols . The known elements have atomic numbers from 1 to 118, conventionally presented as Arabic numerals . Since

11760-429: The top of the column while the least volatile chemicals to vaporize condense in the lowest portion. On the right is a picture illustrating the design of a distillation tower . The difference in volatility between water and ethanol has traditionally been used in the refinement of drinking alcohol . In order to increase the concentration of ethanol in the product, alcohol makers would heat the initial alcohol mixture to

11872-615: The universe at large, in the spectra of stars and also supernovae, where short-lived radioactive elements are newly being made. The first 94 elements have been detected directly on Earth as primordial nuclides present from the formation of the Solar System , or as naturally occurring fission or transmutation products of uranium and thorium. The remaining 24 heavier elements, not found today either on Earth or in astronomical spectra, have been produced artificially: all are radioactive, with short half-lives; if any of these elements were present at

11984-471: The white (but not red) phosphorus – a process now called chemiluminescence . Phosphorus is classified as a pnictogen , together with nitrogen , arsenic , antimony , bismuth , and moscovium . Phosphorus is an element essential to sustaining life largely through phosphates , compounds containing the phosphate ion, PO 4 . Phosphates are a component of DNA , RNA , ATP , and phospholipids , complex compounds fundamental to cells . Elemental phosphorus

12096-528: The work of Dmitri Mendeleev , a Russian chemist who published the first recognizable periodic table in 1869. This table organizes the elements by increasing atomic number into rows (" periods ") in which the columns (" groups ") share recurring ("periodic") physical and chemical properties . The periodic table summarizes various properties of the elements, allowing chemists to derive relationships between them and to make predictions about elements not yet discovered, and potential new compounds. By November 2016,

12208-439: The yellowish liquids PCl 3 and PBr 3 , and the solid PI 3 . These materials are moisture sensitive, hydrolysing to give phosphorous acid . The trichloride, a common reagent, is produced by chlorination of white phosphorus: The trifluoride is produced from the trichloride by halide exchange. PF 3 is toxic because it binds to haemoglobin . Phosphorus(III) oxide , P 4 O 6 (also called tetraphosphorus hexoxide)

12320-592: Was first isolated as white phosphorus in 1669. In white phosphorus, phosphorus atoms are arranged in groups of 4, written as P 4 . White phosphorus emits a faint glow when exposed to oxygen – hence, a name, taken from Greek mythology, Φωσφόρος meaning 'light-bearer' (Latin Lucifer ), referring to the " Morning Star ", the planet Venus . The term phosphorescence , meaning glow after illumination, has its origin in phosphorus, although phosphorus itself does not exhibit phosphorescence: phosphorus glows due to oxidation of

12432-410: Was first isolated from human urine , and bone ash was an important early phosphate source. Phosphate mines contain fossils because phosphate is present in the fossilized deposits of animal remains and excreta. Low phosphate levels are an important limit to growth in a number of plant ecosystems. The vast majority of phosphorus compounds mined are consumed as fertilisers . Phosphate is needed to replace

12544-536: Was not known since ancient times, is credited to the German alchemist Hennig Brand in 1669, although others might have discovered phosphorus around the same time. Brand experimented with urine , which contains considerable quantities of dissolved phosphates from normal metabolism. Working in Hamburg , Brand attempted to create the fabled philosopher's stone through the distillation of some salts by evaporating urine, and in

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