Potassium hexafluorogermanate

Crystal structure
__ K +      __ Ge 4+      __ F -
Crystal system	trigonal
Space group	P 3 m 1 (No. 164)
Lattice parameters	a = 5.62 Å , c = 4.65 Å
General
Surname	Potassium hexafluorogermanate
other names	Dipotassium hexafluorogermanate Potassium hexafluoridogermanate ( IUPAC )
Ratio formula	K 2 [GeF 6 ]
Brief description	white solid
External identifiers / databases
CAS number 7783-73-5 PubChem 71310095 Wikidata Q4134934
properties
Molar mass	264.83 g mol −1
Physical state	firmly
Melting point	730 ° C
boiling point	835 ° C
solubility	little in water (5.4 g l −1 at 18 ° C) insoluble in ethanol
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potassium hexafluorogermanate is an inorganic chemical compound of potassium from the group of germanates .

Extraction and presentation

Potassium hexafluorogermanate can be obtained by reacting germanium dioxide with hydrofluoric acid and potassium chloride .

${\displaystyle \mathrm {GeO_{2}+6\ HF+2\ KCl\longrightarrow K_{2}[GeF_{6}]+2\ HCl+2\ H_{2}O} }$

properties

Potassium hexafluorogermanate is a white, non-hygroscopic solid that is sparingly soluble in water. 5.4 g / l of water dissolve at 18 ° C and 25.8 g / l of water at 100 ° C. It occurs in three modifications, the conversions taking place at 240 ° C and 500 ° C. At room temperature there is a trigonal crystal structure with the space group P 3 m 1 (space group no. 164) and the lattice parameters a = 5.62 Å and c = 4.65 Å.

Individual evidence

1. ↑ ^{a b} Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 231.
2. ↑ ^{a b c d e} data sheet Potassium hexafluorogermanate from Sigma-Aldrich , accessed on May 25, 2017 ( PDF ).
3. ^ ^{A b c} Gmelin's Handbook of Inorganic Chemistry, Germanium, System Number 45, Eighth Edition, Verlag Chemie GmbH, Berlin 1931, page 60.
4. ^ Peter Paetzold: Chemistry: An introduction . Walter de Gruyter, 2009, ISBN 3-11-021135-1 , p. 217 ( limited preview in Google Book search).
5. ↑ JL Hoard, WB Vincent: Structures of Complex Fluorides. Potassium Hexafluogermanate and Ammonium Hexafluogermanate. In: Journal of the American Chemical Society , 61 (10), 1939, pp. 2849-2852, doi: 10.1021 / ja01265a082 .