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48-492: 3,4-Methylenedioxyphenylpropan-2-one or piperonyl methyl ketone ( MDP2P or PMK ) is a chemical compound consisting of a phenylacetone moiety substituted with a methylenedioxy functional group . It is commonly synthesized from either safrole (which, for comparison, is 3-[3,4-(methylenedioxy)phenyl]-2-propene) or its isomer isosafrole via oxidation using the Wacker oxidation or peroxyacid oxidation methods. MDP2P

96-424: A chemical compound ; the concept is most readily understood when considering pure chemical substances . It follows from their being composed of fixed proportions of two or more types of atoms that chemical compounds can be converted, via chemical reaction , into compounds or substances each having fewer atoms. A chemical formula is a way of expressing information about the proportions of atoms that constitute

144-419: A solid-state reaction , or the electron transfer reaction of reactive metals with reactive non-metals, such as halogen gases. Ionic compounds typically have high melting and boiling points , and are hard and brittle . As solids they are almost always electrically insulating , but when melted or dissolved they become highly conductive , because the ions are mobilized. An intermetallic compound

192-466: A ... white Powder ... with Sulphur it will compose a blood-red and volatile Cinaber. And yet out of all these exotick Compounds, we may recover the very same running Mercury. Boyle used the concept of "corpuscles"—or "atomes", as he also called them—to explain how a limited number of elements could combine into a vast number of compounds: If we assigne to the Corpuscles, whereof each Element consists,

240-417: A blend of them). All mixtures can be characterized as being separable by mechanical means (e.g. purification , distillation , electrolysis , chromatography , heat , filtration , gravitational sorting, centrifugation ). Mixtures differ from chemical compounds in the following ways: In the example of sand and water, neither one of the two substances changed in any way when they are mixed. Although

288-530: A compound molecule, using the standard chemical symbols with numerical subscripts . Many chemical compounds have a unique CAS number identifier assigned by the Chemical Abstracts Service . Globally, more than 350,000 chemical compounds (including mixtures of chemicals) have been registered for production and use. The term "compound"—with a meaning similar to the modern—has been used at least since 1661 when Robert Boyle's The Sceptical Chymist

336-412: A continuous three-dimensional network, usually in a crystalline structure . Ionic compounds containing basic ions hydroxide (OH ) or oxide (O ) are classified as bases. Ionic compounds without these ions are also known as salts and can be formed by acid–base reactions . Ionic compounds can also be produced from their constituent ions by evaporation of their solvent , precipitation , freezing ,

384-712: A different chemical composition by interaction with a second chemical compound via a chemical reaction . In this process, bonds between atoms are broken in both of the interacting compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as AB + CD → AD + CB , where A, B, C, and D are each unique atoms; and AB, AD, CD, and CB are each unique compounds. Mixture Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds , without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup. Despite

432-413: A foam, these are a solid and a fluid, or a liquid and a gas. On larger scales both constituents are present in any region of the mixture, and in a well-mixed mixture in the same or only slightly varying concentrations. On a microscopic scale, however, one of the constituents is absent in almost any sufficiently small region. (If such absence is common on macroscopic scales, the combination of the constituents

480-458: A homogeneous mixture, a solution has one phase (solid, liquid, or gas), although the phase of the solute and solvent may initially have been different (e.g., salt water). Gases exhibit by far the greatest space (and, consequently, the weakest intermolecular forces) between their atoms or molecules; since intermolecular interactions are minuscule in comparison to those in liquids and solids, dilute gases very easily form solutions with one another. Air

528-566: A particular chemical compound, using chemical symbols for the chemical elements, and subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is H 2 O. In the case of non-stoichiometric compounds , the proportions may be reproducible with regard to their preparation, and give fixed proportions of their component elements, but proportions that are not integral [e.g., for palladium hydride , PdH x (0.02 < x < 0.58)]. Chemical compounds have

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576-796: A peculiar size and shape ... such ... Corpuscles may be mingled in such various Proportions, and ... connected so many ... wayes, that an almost incredible number of ... Concretes may be compos’d of them. In his Logick , published in 1724, the English minister and logician Isaac Watts gave an early definition of chemical element, and contrasted element with chemical compound in clear, modern terms. Among Substances, some are called Simple, some are Compound ... Simple Substances ... are usually called Elements, of which all other Bodies are compounded: Elements are such Substances as cannot be resolved, or reduced, into two or more Substances of different Kinds. ... Followers of Aristotle made Fire, Air, Earth and Water to be

624-496: A positively charged cation . The nonmetal will gain the electrons from the metal, making the nonmetal a negatively charged anion . As outlined, ionic bonds occur between an electron donor, usually a metal, and an electron acceptor, which tends to be a nonmetal. Hydrogen bonding occurs when a hydrogen atom bonded to an electronegative atom forms an electrostatic connection with another electronegative atom through interacting dipoles or charges. A compound can be converted to

672-402: A single phase . A solution is a special type of homogeneous mixture where the ratio of solute to solvent remains the same throughout the solution and the particles are not visible with the naked eye, even if homogenized with multiple sources. In solutions, solutes will not settle out after any period of time and they cannot be removed by physical methods, such as a filter or centrifuge . As

720-447: A solid state dependent on how low the temperature of the environment is. A covalent bond , also known as a molecular bond, involves the sharing of electrons between two atoms. Primarily, this type of bond occurs between elements that fall close to each other on the periodic table of elements , yet it is observed between some metals and nonmetals. This is due to the mechanism of this type of bond. Elements that fall close to each other on

768-469: A unique and defined chemical structure held together in a defined spatial arrangement by chemical bonds . Chemical compounds can be molecular compounds held together by covalent bonds , salts held together by ionic bonds , intermetallic compounds held together by metallic bonds , or the subset of chemical complexes that are held together by coordinate covalent bonds . Pure chemical elements are generally not considered chemical compounds, failing

816-541: Is a chemical substance composed of many identical molecules (or molecular entities ) containing atoms from more than one chemical element held together by chemical bonds . A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction , which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how

864-457: Is a dispersed medium , not a mixture.) One can distinguish different characteristics of heterogeneous mixtures by the presence or absence of continuum percolation of their constituents. For a foam, a distinction is made between reticulated foam in which one constituent forms a connected network through which the other can freely percolate, or a closed-cell foam in which one constituent is present as trapped in small cells whose walls are formed by

912-403: Is a matter of the scale of sampling. On a coarse enough scale, any mixture can be said to be homogeneous, if the entire article is allowed to count as a "sample" of it. On a fine enough scale, any mixture can be said to be heterogeneous, because a sample could be as small as a single molecule. In practical terms, if the property of interest of the mixture is the same regardless of which sample of it

960-403: Is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elements. Intermetallics are generally hard and brittle, with good high-temperature mechanical properties. They can be classified as stoichiometric or nonstoichiometric intermetallic compounds. A coordination complex consists of a central atom or ion, which is usually metallic and is called

1008-439: Is an example of a solution as well: a homogeneous mixture of gaseous nitrogen solvent, in which oxygen and smaller amounts of other gaseous solutes are dissolved. Mixtures are not limited in either their number of substances or the amounts of those substances, though in a homogeneous mixture the solute-to-solvent proportion can only reach a certain point before the mixture separates and becomes heterogeneous. A homogeneous mixture

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1056-454: Is called homogeneous, whereas a mixture of non-uniform composition and of which the components can be easily identified, such as sand in water, it is called heterogeneous. In addition, " uniform mixture " is another term for homogeneous mixture and " non-uniform mixture " is another term for heterogeneous mixture . These terms are derived from the idea that a homogeneous mixture has a uniform appearance , or only one visible phase , because

1104-579: Is characterized by uniform dispersion of its constituent substances throughout; the substances exist in equal proportion everywhere within the mixture. Differently put, a homogeneous mixture will be the same no matter from where in the mixture it is sampled. For example, if a solid-liquid solution is divided into two halves of equal volume , the halves will contain equal amounts of both the liquid medium and dissolved solid (solvent and solute). In physical chemistry and materials science , "homogeneous" more narrowly describes substances and mixtures which are in

1152-493: Is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions . These can be simple ions such as the sodium (Na ) and chloride (Cl ) in sodium chloride , or polyatomic species such as the ammonium ( NH 4 ) and carbonate ( CO 3 ) ions in ammonium carbonate . Individual ions within an ionic compound usually have multiple nearest neighbours, so are not considered to be part of molecules, but instead part of

1200-412: Is one such example: it can be more specifically described as a gaseous solution of oxygen and other gases dissolved in nitrogen (its major component). The basic properties of solutions are as drafted under: Examples of heterogeneous mixtures are emulsions and foams . In most cases, the mixture consists of two main constituents. For an emulsion, these are immiscible fluids such as water and oil. For

1248-526: Is taken for the examination used, the mixture is homogeneous. Gy's sampling theory quantitatively defines the heterogeneity of a particle as: where h i {\displaystyle h_{i}} , c i {\displaystyle c_{i}} , c batch {\displaystyle c_{\text{batch}}} , m i {\displaystyle m_{i}} , and m aver {\displaystyle m_{\text{aver}}} are respectively:

1296-497: Is unstable at room temperature and must be kept in the freezer in order to be preserved properly. MDP2P is a precursor in the chemical synthesis of the methylenedioxyphenethylamine (MDxx) class of compounds, the classic example of which is 3,4-methylenedioxy- N -methylamphetamine (MDMA), and is also an intermediate between the MDxx family and their slightly more distant precursor safrole or isosafrole. On account of its relation to

1344-452: The coordination centre , and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents. Many metal-containing compounds, especially those of transition metals , are coordination complexes. A coordination complex whose centre is a metal atom is called a metal complex of d block element. Compounds are held together through a variety of different types of bonding and forces. The differences in

1392-449: The oxygen molecule (O 2 ); or it may be heteronuclear , a chemical compound composed of more than one element, as with water (two hydrogen atoms and one oxygen atom; H 2 O). A molecule is the smallest unit of a substance that still carries all the physical and chemical properties of that substance. An ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding . The compound

1440-459: The Earth. Other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. A molecule may be homonuclear , that is, it consists of atoms of one chemical element, as with two atoms in

1488-712: The MDxx chemical class, MDP2P, as well as safrole and isosafrole, are in the United States (U.S.) Drug Enforcement Administration (DEA) List I of Chemicals of the Controlled Substances Act (CSA) via the Chemical Diversion and Trafficking Act (CDTA). It is also considered a category 1 precursor in the European Union. This pharmacology -related article is a stub . You can help Misplaced Pages by expanding it . Chemical compound A chemical compound

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1536-524: The Truth ;; tho' they are not all agreed ... Compound Substances are made up of two or more simple Substances ... So a Needle is simple Body, being made only of Steel; but a Sword or a Knife is a compound because its ... Handle is made of Materials different from the Blade. Any substance consisting of two or more different types of atoms ( chemical elements ) in a fixed stoichiometric proportion can be termed

1584-461: The average mass of a particle in the population. During sampling of heterogeneous mixtures of particles, the variance of the sampling error is generally non-zero. Pierre Gy derived, from the Poisson sampling model, the following formula for the variance of the sampling error in the mass concentration in a sample: in which V is the variance of the sampling error, N is the number of particles in

1632-431: The constituent atoms are bonded together. Molecular compounds are held together by covalent bonds ; ionic compounds are held together by ionic bonds ; intermetallic compounds are held together by metallic bonds ; coordination complexes are held together by coordinate covalent bonds . Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in

1680-472: The fact that there are no chemical changes to its constituents, the physical properties of a mixture, such as its melting point , may differ from those of the components. Some mixtures can be separated into their components by using physical (mechanical or thermal) means. Azeotropes are one kind of mixture that usually poses considerable difficulties regarding the separation processes required to obtain their constituents (physical or chemical processes or, even

1728-400: The fixed ratios. Many solid chemical substances—for example many silicate minerals —are chemical substances, but do not have simple formulae reflecting chemically bonding of elements to one another in fixed ratios; even so, these crystalline substances are often called " non-stoichiometric compounds ". It may be argued that they are related to, rather than being chemical compounds, insofar as

1776-508: The four Elements, of which all earthly Things were compounded; and they suppos'd the Heavens to be a Quintessence, or fifth sort of Body, distinct from all these : But, since experimental Philosophy ... have been better understood, this Doctrine has been abundantly refuted. The Chymists make Spirit, Salt, Sulphur, Water and Earth to be their five Elements, because they can reduce all terrestrial Things to these five : This seems to come nearer

1824-400: The heterogeneity of the i {\displaystyle i} th particle of the population, the mass concentration of the property of interest in the i {\displaystyle i} th particle of the population, the mass concentration of the property of interest in the population, the mass of the i {\displaystyle i} th particle in the population, and

1872-422: The other constituents. A similar distinction is possible for emulsions. In many emulsions, one constituent is present in the form of isolated regions of typically a globular shape, dispersed throughout the other constituent. However, it is also possible each constituent forms a large, connected network. Such a mixture is then called bicontinuous . Making a distinction between homogeneous and heterogeneous mixtures

1920-471: The particles are evenly distributed. However, a heterogeneous mixture has non-uniform composition , and its constituent substances are easily distinguishable from one another (often, but not always, in different phases). Several solid substances, such as salt and sugar , dissolve in water to form a special type of homogeneous mixture called a solution , in which there is both a solute (dissolved substance) and solvent (dissolving medium) present. Air

1968-536: The periodic table tend to have similar electronegativities , which means they have a similar affinity for electrons. Since neither element has a stronger affinity to donate or gain electrons, it causes the elements to share electrons so both elements have a more stable octet . Ionic bonding occurs when valence electrons are completely transferred between elements. Opposite to covalent bonding, this chemical bond creates two oppositely charged ions. The metals in ionic bonding usually lose their valence electrons, becoming

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2016-425: The population (before the sample was taken), q   i is the probability of including the i th particle of the population in the sample (i.e. the first-order inclusion probability of the i th particle), m   i is the mass of the i th particle of the population and a   i is the mass concentration of the property of interest in the i th particle of the population. The above equation for

2064-408: The sand is in the water it still keeps the same properties that it had when it was outside the water. The following table shows the main properties and examples for all possible phase combinations of the three "families" of mixtures : Mixtures can be either homogeneous or heterogeneous : a mixture of uniform composition and in which all components are in the same phase, such as salt in water,

2112-494: The two or more atom requirement, though they often consist of molecules composed of multiple atoms (such as in the diatomic molecule H 2 , or the polyatomic molecule S 8 , etc.). Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): its CAS number . There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, which require

2160-455: The types of bonds in compounds differ based on the types of elements present in the compound. London dispersion forces are the weakest force of all intermolecular forces . They are temporary attractive forces that form when the electrons in two adjacent atoms are positioned so that they create a temporary dipole . Additionally, London dispersion forces are responsible for condensing non polar substances to liquids, and to further freeze to

2208-421: The variability in their compositions is often due to either the presence of foreign elements trapped within the crystal structure of an otherwise known true chemical compound , or due to perturbations in structure relative to the known compound that arise because of an excess of deficit of the constituent elements at places in its structure; such non-stoichiometric substances form most of the crust and mantle of

2256-416: The variance of the sampling error is an approximation based on a linearization of the mass concentration in a sample. In the theory of Gy, correct sampling is defined as a sampling scenario in which all particles have the same probability of being included in the sample. This implies that q   i no longer depends on  i , and can therefore be replaced by the symbol  q . Gy's equation for

2304-409: Was published. In this book, Boyle variously used the terms "compound", "compounded body", "perfectly mixt body", and "concrete". "Perfectly mixt bodies" included for example gold, lead, mercury, and wine. While the distinction between compound and mixture is not so clear, the distinction between element and compound is a central theme. Quicksilver ... with Aqua fortis will be brought into

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