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The direct reaction of hydrocarbons with fluorine gas can be dangerously reactive, so the temperature may need to be lowered even to −150 °C (−240 °F). [115] "Solid fluorine carriers", compounds that can release fluorine upon heating, notably cobalt trifluoride, [116] may be used instead, or hydrogen
Hydrogen fluoride is typically produced by the reaction between sulfuric acid and pure grades of the mineral fluorite: [14] CaF 2 + H 2 SO 4 → 2 HF + CaSO 4. About 20% of manufactured HF is a byproduct of fertilizer production, which generates hexafluorosilicic acid. This acid can be degraded to release HF thermally and by hydrolysis: H 2 SiF ...
With the formula AlF 3 ·xH 2 O, these compounds include monohydrate (x = 1), two polymorphs of the trihydrate (x = 3), a hexahydrate (x = 6), and a nonahydrate (x = 9). [10] The majority of aluminium fluoride is produced by treating alumina with hydrogen fluoride at 700 °C: [4] Hexafluorosilicic acid may also be used make aluminium fluoride. [11]
Owing to the expense of refining pure fluorine, most commercial applications use fluorine compounds, with about half of mined fluorite used in steelmaking. The rest of the fluorite is converted into hydrogen fluoride en route to various organic fluorides, or into cryolite , which plays a key role in aluminium refining .
The standard Gibbs free energy of formation (G f °) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 °C).
This neutralization reaction forms hydrogen fluoride (HF), the conjugate acid of fluoride. In aqueous solution, fluoride has a pK b value of 10.8. It is therefore a weak base, and tends to remain as the fluoride ion rather than generating a substantial amount of hydrogen fluoride. That is, the following equilibrium favours the left-hand side in ...
This is another reason for the high chemical stability of polyfluorinated compounds. Fluorine has the highest electronegativity of all elements: 3.98. [1] This causes the high dipole moment of C-F bond (1.41 D [1]). Fluorine has the lowest polarizability of all atoms: 0.56 10 −24 cm 3. [1]
Aluminium monofluoride, also known as fluoridoaluminium, is the chemical compound with the formula AlF. This elusive species is formed by the reaction between aluminium trifluoride and metallic aluminium at elevated temperatures but quickly reverts to the reactants when cooled. [ 1 ]