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51-497: The 2:1 molar mixture forms a stoichiometric compound, Li 2 [BeF 4 ] ( lithium tetrafluoroberyllate ), which has a melting point of 459 °C (858 °F), a boiling point of 1,430 °C (2,610 °F), and a density of 1.94 g/cm (0.070 lb/cu in). Its volumetric heat capacity , 4540 kJ/(m·K), is similar to that of water, more than four times that of sodium, and more than 200 times that of helium at typical reactor conditions. Its specific heat capacity

102-589: A public company via an initial public offering . The Space Shuttle program, which ended in 2011, used total of 47 parts made from Haynes 188 alloy and 7 from Haynes' Hastelloy B alloy in its engines. Hastelloy C-22 alloy was used for the fuel line bellows that assisted in achieving takeoff. In 2015, the company acquired Leveltek Processing. In 2016, the company expanded its operations in LaPorte, Indiana. The expansion created 52 jobs. In 2018, chairman Michael Shor became President and chief executive officer of

153-610: A beta particle and two alpha particles. Beryllium will occasionally disintegrate into two alpha particles and two neutrons when hit by a fast neutron . Fluorine has a non-negligible cross section for (α,n) reactions, which needs to be taken into account when calculating neutronics . In the liquid fluoride thorium reactor (LFTR) it serves as solvent for the fissile and fertile material fluoride salts, as well as moderator and coolant. Some other designs (sometimes called molten-salt cooled reactors) use it as coolant, but have conventional solid nuclear fuel instead of dissolving it in

204-454: A century earlier. In chemistry, it has been known since Proust's law of definite proportions (1794) that knowledge of the mass of each of the components in a chemical system is not sufficient to define the system. Amount of substance can be described as mass divided by Proust's "definite proportions", and contains information that is missing from the measurement of mass alone. As demonstrated by Dalton's law of partial pressures (1803),

255-450: A fact that greatly aided their acceptance: It was not necessary for a chemist to subscribe to atomic theory (an unproven hypothesis at the time) to make practical use of the tables. This would lead to some confusion between atomic masses (promoted by proponents of atomic theory) and equivalent weights (promoted by its opponents and which sometimes differed from relative atomic masses by an integer factor), which would last throughout much of

306-557: A lesser extent fluorine make FLiBe an effective neutron moderator . As natural lithium contains ~7.5% lithium-6 , which tends to absorb neutrons producing alpha particles and tritium , nearly pure lithium-7 is used to give the FLiBe a small neutron absorption cross section ; e.g. the MSRE secondary coolant was 99.993% lithium-7 FLiBe. When Li-7 does absorb a neutron, it nigh-instantaneously decays via successive beta- and then alpha decay into

357-414: A mass of exactly 12  g . The four different definitions were equivalent to within 1%. Because a dalton , a unit commonly used to measure atomic mass , is exactly 1/12 of the mass of a carbon-12 atom, this definition of the mole entailed that the mass of one mole of a compound or element in grams was numerically equal to the average mass of one molecule or atom of the substance in daltons, and that

408-449: A measurement of mass is not even necessary to measure the amount of substance (although in practice it is usual). There are many physical relationships between amount of substance and other physical quantities, the most notable one being the ideal gas law (where the relationship was first demonstrated in 1857). The term "mole" was first used in a textbook describing these colligative properties . Developments in mass spectrometry led to

459-448: A special name derived from the mole is the katal , defined as one mole per second of catalytic activity . Like other SI units, the mole can also be modified by adding a metric prefix that multiplies it by a power of 10 : One femtomole is exactly 602,214,076 molecules; attomole and smaller quantities cannot be exactly realized. The yoctomole, equal to around 0.6 of an individual molecule, did make appearances in scientific journals in

510-704: A subsidiary of Acerinox headquartered in Kokomo, Indiana , is one of the largest producers of corrosion -resistant and high-temperature alloys . In addition to Kokomo, Haynes has manufacturing facilities in Arcadia, Louisiana , Laporte, Indiana , and Mountain Home, North Carolina . The Kokomo facility specializes in flat products, the Arcadia facility in tubular products, and the Mountain Home facility in wire products. In fiscal year 2018,

561-483: A substance is equal to its relative atomic (or molecular) mass multiplied by the molar mass constant , which is almost exactly 1 g/mol. Like chemists, chemical engineers use the unit mole extensively, but different unit multiples may be more suitable for industrial use. For example, the SI unit for volume is the cubic metre, a much larger unit than the commonly used litre in the chemical laboratory. When amount of substance

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612-509: A substance was redefined as containing "exactly 6.022 140 76 × 10 elementary entities" of that substance. Since its adoption into the International System of Units in 1971, numerous criticisms of the concept of the mole as a unit like the metre or the second have arisen: October 23, denoted 10/23 in the US, is recognized by some as Mole Day . It is an informal holiday in honor of

663-510: A substance. One mole contains exactly 6.022 140 76 × 10 elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can be atoms, molecules, ions, ion pairs, or other particles . The number of particles in a mole is the Avogadro number (symbol N 0 ) and the numerical value of the Avogadro constant (symbol N A ) expressed in mol . The value was chosen on

714-419: Is 2414.17 J/(kg·K), or about 60% that of water. Its appearance is white to transparent, with crystalline grains in a solid state, morphing into a completely clear liquid upon melting. However, soluble fluorides such as UF 4 and NiF 2 , can dramatically change the salt's color in both solid and liquid state. This made spectrophotometry a viable analysis tool, and it was employed extensively during

765-438: Is also expressed in kmol (1000 mol) in industrial-scaled processes, the numerical value of molarity remains the same, as kmol m 3 = 1000  mol 1000  L = mol L {\textstyle {\frac {\text{kmol}}{{\text{m}}^{3}}}={\frac {1000{\text{ mol}}}{1000{\text{ L}}}}={\frac {\text{mol}}{\text{L}}}} . Chemical engineers once used

816-410: Is an innate and measurable voltage in the salt which is the prime indicator of the corrosion potential in salt. Usually, the reaction is set at zero volts. This reaction proves convenient in a laboratory setting and can be used to set the salt to zero through bubbling a 1:1 mixture of hydrogen fluoride and hydrogen through the salt. Occasionally the reaction: is used as a reference. Regardless of where

867-544: Is commonly expressed by its molar concentration , defined as the amount of dissolved substance per unit volume of solution, for which the unit typically used is mole per litre (mol/L). The number of entities (symbol N ) in a one-mole sample equals the Avogadro number (symbol N 0 ), a dimensionless quantity . Historically, N 0 approximates the number of nucleons ( protons or neutrons ) in one gram of ordinary matter . The Avogadro constant (symbol N A = N 0 /mol ) has numerical multiplier given by

918-408: Is widely used in chemistry as a convenient way to express amounts of reactants and amounts of products of chemical reactions . For example, the chemical equation 2 H 2 + O 2 → 2 H 2 O can be interpreted to mean that for each 2 mol molecular hydrogen (H 2 ) and 1 mol molecular oxygen (O 2 ) that react, 2 mol of water (H 2 O) form. The concentration of a solution

969-479: The 2019 revision of the SI , which redefined the mole by fixing the value of the Avogadro constant, making it very nearly equivalent to but no longer exactly equal to the gram-mole), but whose name and symbol adopt the SI convention for standard multiples of metric units – thus, kmol means 1000 mol. This is equivalent to the use of kg instead of g. The use of kmol is not only for "magnitude convenience" but also makes

1020-414: The kilogram-mole (notation kg-mol ), which is defined as the number of entities in 12 kg of C, and often referred to the mole as the gram-mole (notation g-mol ), then defined as the number of entities in 12 g of C, when dealing with laboratory data. Late 20th-century chemical engineering practice came to use the kilomole (kmol), which was numerically identical to the kilogram-mole (until

1071-480: The 14th CGPM. Before the 2019 revision of the SI , the mole was defined as the amount of substance of a system that contains as many elementary entities as there are atoms in 12 grams of carbon-12 (the most common isotope of carbon ). The term gram-molecule was formerly used to mean one mole of molecules, and gram-atom for one mole of atoms. For example, 1 mole of MgBr 2 is 1 gram-molecule of MgBr 2 but 3 gram-atoms of MgBr 2 . In 2011,

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1122-851: The 24th meeting of the General Conference on Weights and Measures (CGPM) agreed to a plan for a possible revision of the SI base unit definitions at an undetermined date. On 16 November 2018, after a meeting of scientists from more than 60 countries at the CGPM in Versailles, France, all SI base units were defined in terms of physical constants. This meant that each SI unit, including the mole, would not be defined in terms of any physical objects but rather they would be defined by physical constants that are, in their nature, exact. Such changes officially came into effect on 20 May 2019. Following such changes, "one mole" of

1173-527: The Avogadro number with the unit reciprocal mole (mol ). The ratio n = N / N A is a measure of the amount of substance (with the unit mole). Depending on the nature of the substance, an elementary entity may be an atom , a molecule , an ion , an ion pair, or a subatomic particle such as a proton . For example, 10 moles of water (a chemical compound ) and 10 moles of mercury (a chemical element ) contain equal numbers of substance, with one atom of mercury for each molecule of water, despite

1224-472: The MSRE operations. The eutectic mixture is slightly greater than 50% BeF 2 and has a melting point of 360 °C (680 °F). This mixture was never used in practice due to the overwhelming increase in viscosity caused by the BeF 2 addition in the eutectic mixture. BeF 2 , which behaves as a glass, is only fluid in salt mixtures containing enough molar percent of Lewis base . Lewis bases, such as

1275-420: The adoption of oxygen-16 as the standard substance, in lieu of natural oxygen. The oxygen-16 definition was replaced with one based on carbon-12 during the 1960s. The International Bureau of Weights and Measures defined the mole as "the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilograms of carbon-12." Thus, by that definition, one mole of pure C had

1326-405: The alkali fluorides, will donate fluoride ions to the beryllium, breaking the glassy bonds which increase viscosity. In FLiBe, beryllium fluoride is able to sequester two fluoride ions from two lithium fluorides in a liquid state, converting it into the tetrafluoroberyllate ion [BeF 4 ] . The chemistry of FLiBe, and other fluoride salts , is unique due to the high temperatures at which

1377-400: The basic SI unit of mol/s were to be used, which would otherwise require the molar mass to be converted to kg/mol. For convenience in avoiding conversions in the imperial (or US customary units ), some engineers adopted the pound-mole (notation lb-mol or lbmol ), which is defined as the number of entities in 12 lb of C. One lb-mol is equal to 453.592 37  g‑mol , which is

1428-458: The basis of the historical definition of the mole as the amount of substance that corresponds to the number of atoms in 12  grams of C , which made the mass of a mole of a compound expressed in grams, numerically equal to the average molecular mass or formula mass of the compound expressed in daltons . With the 2019 revision of the SI , the numerical equivalence is now only approximate but may be assumed for all practical purposes. The mole

1479-484: The chemical convenience of having oxygen as the primary atomic mass standard became ever more evident with advances in analytical chemistry and the need for ever more accurate atomic mass determinations. The name mole is an 1897 translation of the German unit Mol , coined by the chemist Wilhelm Ostwald in 1894 from the German word Molekül ( molecule ). The related concept of equivalent mass had been in use at least

1530-577: The company invented its first alloy under the Hastelloy brand, derived from the words "Haynes Stellite Alloy". In 1927, Charles Lindbergh 's aircraft, the Spirit of St. Louis , which included hard-surfaced engine valves manufactured by Haynes, crossed the Atlantic Ocean . In 1970, Cabot Corporation purchased the company. In 1989, the investment banking firm of Morgan, Lewis, Githens, and Ahn purchased

1581-528: The company's revenues were derived from the aerospace (52.1%), chemical processing (18.2%), industrial gas turbine (12.0%) and other (12.3%) industries. The company's alloys are primarily marketed under the Hastelloy and the Haynes brands. They are based on nickel , but also include cobalt , chromium , molybdenum , tungsten , iron , silicon , manganese , carbon , aluminum , and/or titanium . The company

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1632-675: The company. In 1997, the Blackstone Group purchased the company. The debt incurred ultimately forced Haynes into bankruptcy in March 2004, from which it emerged 5 months later in August 2004. In 1999, the company opened an office in Singapore, its first sales office in Asia. In 2004, the company acquired Branford Wire & Manufacturing of Mountain Home, North Carolina . In March 2007, Haynes became

1683-422: The definition of the gram was not mathematically tied to that of the dalton, the number of molecules per mole N A (the Avogadro constant) had to be determined experimentally. The experimental value adopted by CODATA in 2010 is N A = 6.022 141 29 (27) × 10  mol . In 2011 the measurement was refined to 6.022 140 78 (18) × 10  mol . The mole was made the seventh SI base unit in 1971 by

1734-484: The equations used for modelling chemical engineering systems coherent . For example, the conversion of a flowrate of kg/s to kmol/s only requires dividing by the molar mass in g/mol (as kg kmol = 1000  g 1000  mol = g mol {\textstyle {\frac {\text{kg}}{\text{kmol}}}={\frac {1000{\text{ g}}}{1000{\text{ mol}}}}={\frac {\text{g}}{\text{mol}}}} ) without multiplying by 1000 unless

1785-431: The main portion of Hastelloy-N , the material of the MSRE. Altering the redox potential of FLiBe can be done in two ways. First, the salt can be forced by physically applying a voltage to the salt with an inert electrode. The second, more common way, is to perform a chemical reaction in the salt which occurs at the desired voltage. For example, redox potential can be altered by sparging hydrogen and hydrogen fluoride into

1836-455: The molten salt. The liquid FLiBe salt was also proposed as a liquid blanket for tritium production and cooling in the ARC fusion reactor , a compact tokamak design by MIT. Mole (unit) The mole (symbol mol ) is a unit of measurement , the base unit in the International System of Units (SI) for amount of substance , a quantity proportional to the number of elementary entities of

1887-613: The nineteenth century. Jöns Jacob Berzelius (1779–1848) was instrumental in the determination of relative atomic masses to ever-increasing accuracy. He was also the first chemist to use oxygen as the standard to which other masses were referred. Oxygen is a useful standard, as, unlike hydrogen, it forms compounds with most other elements, especially metals . However, he chose to fix the atomic mass of oxygen as 100, which did not catch on. Charles Frédéric Gerhardt (1816–56), Henri Victor Regnault (1810–78) and Stanislao Cannizzaro (1826–1910) expanded on Berzelius' works, resolving many of

1938-434: The number of daltons in a gram was equal to the number of elementary entities in a mole. Because the mass of a nucleon (i.e. a proton or neutron ) is approximately 1 dalton and the nucleons in an atom's nucleus make up the overwhelming majority of its mass, this definition also entailed that the mass of one mole of a substance was roughly equivalent to the number of nucleons in one atom or molecule of that substance. Since

1989-472: The problems of unknown stoichiometry of compounds, and the use of atomic masses attracted a large consensus by the time of the Karlsruhe Congress (1860). The convention had reverted to defining the atomic mass of hydrogen as 1, although at the level of precision of measurements at that time – relative uncertainties of around 1% – this was numerically equivalent to the later standard of oxygen = 16. However

2040-451: The reactions and While BeF 2 is a very stable chemical compound, the formation of oxides, hydroxides, and hydrogen fluoride reduce the stability and inertness of the salt. This leads to corrosion. Its important to understand that all dissolved species in these two reactions cause the corrosion—not just the hydrogen fluoride. This is because all dissolved components alter the reduction potential or redox potential. The redox potential

2091-429: The reactions occur, the ionic nature of the salt, and the reversibility of many of the reactions. At the most basic level, FLiBe melts and complexes itself through This reaction occurs upon initial melting. However, if the components are exposed to air they will absorb moisture. This moisture plays a negative role at high temperature by converting BeF 2 , and to a lesser extent LiF, into an oxide or hydroxide through

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2142-432: The reactions of concern would be the fluorination of container and subsequent dissolution of these metal fluorides. The dissolution of the metal fluorides then alters the redox potential. This process continues until an equilibrium between metals and salt is reached. It is essential that a salt's redox potential be kept as far away from fluorination reactions as possible, and that metals in contact with salt be as far away from

2193-577: The salt or by dipping a metal into the salt. As a molten salt it can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure . Notably, its optical transparency allows easy visual inspection of anything immersed in the coolant as well as any impurities dissolved in it. Unlike sodium or potassium metals, which can also be used as high-temperature coolants, it does not violently react with air or water. FLiBe salt has low hygroscopy and solubility in water. The low atomic weight of lithium , beryllium and to

2244-457: The salt's redox potential as possible in order to prevent excessive corrosion. The easiest method to prevent undesirable reactions is to pick materials whose reaction voltages are far from the redox potential of the salt in the salt's worst case. Some of these materials are tungsten, carbon, molybdenum, platinum, iridium, and nickel. Of all these materials, only two are affordable and weldable: nickel and molybdenum. These two elements were chosen as

2295-416: The same numerical value as the number of grams in an international avoirdupois pound . Greenhouse and growth chamber lighting for plants is sometimes expressed in micromoles per square metre per second, where 1 mol photons ≈ 6.02 × 10 photons. The obsolete unit einstein is variously defined as the energy in one mole of photons and also as simply one mole of photons. The only SI derived unit with

2346-435: The solid is composed of a certain number of moles of such entities. In yet other cases, such as diamond , where the entire crystal is essentially a single molecule, the mole is still used to express the number of atoms bound together, rather than a count of molecules. Thus, common chemical conventions apply to the definition of the constituent entities of a substance, in other cases exact definitions may be specified. The mass of

2397-489: The two quantities having different volumes and different masses. The mole corresponds to a given count of entities. Usually, the entities counted are chemically identical and individually distinct. For example, a solution may contain a certain number of dissolved molecules that are more or less independent of each other. However, the constituent entities in a solid are fixed and bound in a lattice arrangement, yet they may be separable without losing their chemical identity. Thus,

2448-404: The unit among chemists. The date is derived from the Avogadro number, which is approximately 6.022 × 10 . It starts at 6:02 a.m. and ends at 6:02 p.m. Alternatively, some chemists celebrate June 2 ( 06/02 ), June 22 ( 6/22 ), or 6 February ( 06.02 ), a reference to the 6.02 or 6.022 part of the constant. Haynes International Haynes International, Inc. ,

2499-459: The year the yocto- prefix was officially implemented. The history of the mole is intertwined with that of units of molecular mass , and the Avogadro constant . The first table of standard atomic weight was published by John Dalton (1766–1844) in 1805, based on a system in which the relative atomic mass of hydrogen was defined as 1. These relative atomic masses were based on the stoichiometric proportions of chemical reaction and compounds,

2550-447: The zero is set, all other reactions which occur in the salt will occur at predictable, known voltages relative to the zero. Therefore, if the redox potential of the salt is close to a specific reaction's voltage, that reaction can be expected to be the predominant reaction. Therefore, it is important to keep a salt's redox potential far away from reactions which are undesirable. For example, in a container alloy of nickel, iron, and chromium,

2601-484: Was founded by Elwood Haynes in 1912 in Kokomo, Indiana, as Haynes Stellite Works. The same year Haynes was awarded two more patents for the more advanced versions of Stellite , which he had originally patented in 1907. In 1915, Elwood Haynes and two local businessmen, Richard Ruddell and James C. Patten, incorporate the business as Haynes Stellite Company. In 1920, the company was acquired by Union Carbide . In 1922,

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