Potassium hexafluorophosphate

Potassium hexafluorophosphate
IUPAC name Potassium hexafluorophosphate
Identifiers
CAS number	17084-13-8
PubChem	23688904
ChemSpider	146640 Y
Jmol-3D images	Image 1
SMILES [K+].F[P-](F)(F)(F)(F)F
InChI InChI=1S/F6P.K/c1-7(2,3,4,5)6;/q-1;+1 Y Key: YZDGRYDIGCWVND-UHFFFAOYSA-N Y InChI=1/F6P.K/c1-7(2,3,4,5)6;/q-1;+1 Key: YZDGRYDIGCWVND-UHFFFAOYAC
Properties
Molecular formula	F6KP
Molar mass	184.0625 g/mol
Appearance	colourless solid
Density	2.75 g/cm3
Melting point	575 °C
Solubility in water	0.432M (25 °C)
Hazards
R-phrases	R20, R21, R22, R34
S-phrases	S26, S27, S36, S37, S39, S45
Main hazards	Toxic
NFPA 704	0 2 0
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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: ^[1]

PCl₅ + KCl + 6 HF → KPF₆ + 6 HCl

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 lipophilicity to its salts. It salts are often less soluble than the closely related tetrafluoroborates.

References

1. ^ Woyski, M. M.; Shenk, W. J.; Pellon, E. R. (1950). "Hexafluorophosphates of Sodium, Ammonium, and Potassium". Inorg. Synth.. Inorganic Syntheses 3: 111–117. doi:10.1002/9780470132340.ch29. ISBN 978-0-470-13234-0.