Potassium hexafluorophosphate
Encyclopedia
Potassium hexafluorophosphate is the chemical compound
with the formula
KPF6. This colourless salt consists of potassium
cations and hexafluorophosphate
anions. It is prepared by the reaction:
This exothermic reaction is conducted in liquid hydrogen fluoride
. The salt is stable in hot alkaline aqueous solution, from which it can be recrystallized. The sodium and ammonium
salts are more soluble in water whereas the rubidium and caesium salts are less so.
KPF6 is a common laboratory source of the hexafluorophosphate anion, a non-coordinating anion
that confers lipophilic
ity to its salts. It salts are often less soluble than the closely related tetrafluoroborate
s.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
KPF6. This colourless salt consists of potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
cations and hexafluorophosphate
Hexafluorophosphate
Hexafluorophosphate is an anion with chemical formula of . This octahedral species is isoelectronic with sulfur hexafluoride, SF6, and is valence isoelectronic with the highly stable superacid anion fluoroantimonate . As a non-coordinating anion, it is a poor nucleophile...
anions. It is prepared by the reaction:
- PCl5 + KClPotassium chlorideThe chemical compound potassium chloride is a metal halide salt composed of potassium and chlorine. In its pure state, it is odorless and has a white or colorless vitreous crystal appearance, with a crystal structure that cleaves easily in three directions. Potassium chloride crystals are...
+ 6 HF → KPF6 + 6 HCl
This exothermic reaction is conducted in liquid hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...
. The salt is stable in hot alkaline aqueous solution, from which it can be recrystallized. The sodium and ammonium
Ammonium
The ammonium cation is a positively charged polyatomic cation with the chemical formula NH. It is formed by the protonation of ammonia...
salts are more soluble in water whereas the rubidium and caesium salts are less so.
KPF6 is a common laboratory source of the hexafluorophosphate anion, a non-coordinating anion
Non-coordinating anion
Anions that interact weakly with cations are termed non-coordinating anions, although a more accurate term is 'weakly coordinating anion'. Non-coordinating anions are useful in studying the reactivity of electrophilic cations. They are commonly found as counterions for cationic metal complexes...
that confers lipophilic
Lipophilic
Lipophilicity, , refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true...
ity to its salts. It salts are often less soluble than the closely related tetrafluoroborate
Tetrafluoroborate
Tetrafluoroborate is the anion BF4−. This tetrahedral species is isoelectronic with tetrafluoromethane, CF4 and tetrafluoroammonium NF4+, and is valence isoelectronic with many stable and important species including the closely related anion perchlorate, ClO4−...
s.