Potassium tetrafluoroborate

Crystal structure
__ K +      __ B 3+      __ F -
Crystal system	orthorhombic
Space group	Pbnm (No. 62, position 3)
Lattice parameters	a = 7.03  Å , b = 8.674 Å, c = 5.496 Å
General
Surname	Potassium tetrafluoroborate
other names	Potassium borofluoride Potassium fluoroborate Potassium tetrafluoroborate Potassium tetrafluoridoborate (current nomenclature)
Ratio formula	K [BF 4 ]
Brief description	white odorless solid
External identifiers / databases
CAS number 14075-53-7 EC number 237-928-2 ECHA InfoCard 100.034.466 PubChem 518872 Wikidata Q11129316
properties
Molar mass	125.91 g mol −1
Physical state	firmly
density	2.5 g cm −3
Melting point	530 ° C (decomposition)
solubility	slightly soluble in water (4.4 g l −1 at 20 ° C)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	5854 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potassium tetrafluoroborate is a chemical compound , more precisely the potassium salt of tetrafluoroboric acid . The correct scientific name for the latest IUPAC - nomenclature is tetrafluoridoborat potassium.

Extraction and presentation

Potassium tetrafluoroborate can be obtained by reaction or neutralization of potassium hydroxide or potassium carbonate with tetrafluoridoboric acid.

${\displaystyle {\ce {KOH + HBF4 -> K[BF_4] + H2O}}}$

${\displaystyle {\ce {K2CO3 + 2HBF4 -> 2K[BF4] + H2O + CO2 ^}}}$

properties

Potassium tetrafluoroborate is a white, odorless solid that is sparingly soluble in water. It decomposes at a temperature above 530 ° C, hydrogen fluoride , boron oxide , potassium oxide and boron fluoride arise. The compound crystallizes in the orthorhombic space group Pbnm (space group no. 62, position 3) with the lattice constants a = 7.03  Å , b = 8.674 Å and c = 5.496 Å. There are four formula units in a unit cell.

use

Potassium tetrafluoroborate is used as solder , cover salt when melting light metal , molding sands when melting aluminum and manganese and is contained in phosphating baths.

Individual evidence

1. ↑ ^{a b} M. JR Clark, H. Lynton: Crystal strucutes of potassium, ammonium, rubidium and cesium tetrafluoroborates . In: Canadian Journal of Chemistry . tape 47 , no. 14 , January 9, 1969, p. 2579-2586 , doi : 10.1139 / v69-426 .
2. ↑ ^{a b c d e f g h} Entry for CAS no. 14075-53-7 in the GESTIS substance database of the IFA , accessed on February 17, 2011 (JavaScript required)
3. ↑ Data sheet potassium tetrafluoroborate from Sigma-Aldrich , accessed on February 17, 2011 ( PDF ).
4. ↑ Toxicological evaluation of tetrafluoroboric acid and salts (PDF) at the professional association raw materials and chemical industry (BG RCI), accessed on August 22, 2012.