Potassium Bifluoride - Wikipedia

Potassium bifluoride

Names
IUPAC name Potassium bifluoride
Other names Potassium hydrogen difluoride
Identifiers
CAS Number	7789-29-9 Y
3D model (JSmol)	Interactive image
ChemSpider	35308426 Y
ECHA InfoCard	100.029.233
EC Number	232-156-2
PubChem CID	11829350
RTECS number	TS6650000
UNII	880X05W53M Y
UN number	1811
CompTox Dashboard (EPA)	DTXSID10894159
InChI InChI=1S/F2H.K/c1-3-2;/q-1;+1 NKey: FLCWRBFUWAZYGV-UHFFFAOYSA-N N
SMILES [H-](F)F.[K+]
Properties
Chemical formula	K[HF2]
Molar mass	78.103 g/mol
Appearance	colourless solid
Odor	slightly acidic
Density	2.37 g/cm3
Melting point	238.7 °C (461.7 °F; 511.8 K)
Boiling point	decomposes
Solubility in water	24.5 g/(100 mL) (0 °C) 30.1 g/(100 mL) (10 °C) 39.2 g/(100 mL) (20 °C) 114.0 g/(100 mL) (80 °C)
Solubility	soluble in ethanol
Structure
Crystal structure	monoclinic
Thermochemistry
Std molarentropy (S⦵298)	45.56 J/(mol·K) [1]
Std enthalpy offormation (ΔfH⦵298)	−417.26 kJ/(mol·K)
Hazards
GHS labelling:[2]
Pictograms
Signal word	Danger
Hazard statements	H301, H310, H314
Precautionary statements	P260, P262, P264, P270, P280, P301+P310, P301+P330+P331, P302+P350, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P322, P330, P361, P363, P405, P501
Flash point	non flammable
Related compounds
Other anions	Potassium fluoride
Other cations	Sodium bifluoride, ammonium bifluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Chemical compound

Potassium bifluoride is the inorganic compound with the formula K[HF2]. This colourless salt consists of the potassium cation (K+) and the bifluoride anion ([HF2]−). The salt is used as an etchant for glass. Sodium bifluoride is related and is also of commercial use as an etchant as well as in cleaning products.[3]

Synthesis and reactions

[edit]

The salt was prepared by Edmond Frémy by treating potassium carbonate or potassium hydroxide with hydrofluoric acid:

2 HF + KOH → K[HF2] + H2O

With one more equivalent of HF, K[H2F3] (CAS RN 12178-06-2, m.p. 71.7 °C[4]) is produced:

HF + K[HF2] → K[H2F3]

Thermal decomposition of K[HF2] gives hydrogen fluoride:

K[HF2] → HF + KF

Applications

[edit]

The industrial production of fluorine entails the electrolysis of molten K[HF2] and K[H2F3].[3] The electrolysis of K[HF2] was first used by Henri Moissan in 1886.

See also

[edit]

• Ammonium bifluoride
• Bifluoride anion

References

[edit]

1. ^ Westrum, Edgar F. Jr.; Pitzer, Kenneth S. (June 1949). "Thermodynamics of the System KHF2-KF-HF, Including Heat Capacities and Entropies of KHF2, and KF. The Nature of the Hydrogen Bond in KHF2". J. Am. Chem. Soc. 71 (6): 1940–1949. doi:10.1021/ja01174a012.
2. ^ "Potassium bifluoride". pubchem.ncbi.nlm.nih.gov. Retrieved 27 December 2021.
3. ^ a b Aigueperse, Jean; Mollard, Paul; Devilliers, Didier; Chemla, Marius; Faron, Robert; Romano, René; Cuer, Jean Pierre (2000). "Fluorine Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a11_307. ISBN 3527306730.
4. ^ Ažman, A.; Ocvirk, A.; Hadži, D.; Giguère, Paul A.; Schneider, Michel (1967-06-15). "Infrared spectra of KH2F3 and the structure of the H2F3− ion". Canadian Journal of Chemistry. 45 (12). Canadian Science Publishing: 1347–1350. doi:10.1139/v67-222. ISSN 0008-4042.

v t e Potassium compounds
H, (pseudo)halogens	KBr KBrO3 KBrO4 KCl KClO KClO2 KClO3 KClO4 KCN KCNO KF KHF2 KH KI KIO3 KIO4 KOCN KSCN
chalcogens	K2O KOH K2O2 KO2 KO3 K2S KHS K2SO3 KHSO3 K2SO4 KHSO4 KHSO5 K2S2O3 K2S2O5 K2S2O7 K2S2O8 K2Se K2SeO4 K2Te K2TeO3 K2Po
pnictogens	KAsO2 KH2AsO4 K3N KN3 KNH2 KNO2 KNO3 K2HPO4 KH2PO3 KH2PO4 K3P KPF6 K3PO4
B, C group	KBF4 K2Al2B2O7 K2Al2O4 K2CO3 KHCO3 K2SiF6 K2SiO3
transition metals	K2ReBr6 KCrO3Cl K4Mo2Cl8 K2OsCl6 K2PtCl4 K2PtCl6 K2ReCl6 K3CrO4 K2CrO4 K3CrO8 K2Cr2O7 K2FeO4 K4[Fe(CN)6]·3H2O K3[Fe(CN)6] K3[Fe(C2O4)3] K2TiF6 K2ReF6 KAsF6 K2ZrF6 K2ReI6 K2[Pt(CN)4] K2MnO4 KMnO4
organic	KHCO2 KCH3CO2 KCF3CO2 KHC2O4 C6H5COOK KC8H5O4 KC12H23O2 KC18H35O2 CF3KO3S

v t e Fluorine compounds
v t e Salts and covalent derivatives of the fluoride ion HF ?HeF2 LiF BeF2 BFBF3B2F4+BO3 CF4CxFy+CO3 NF3FN3N2F2NFN2F4NF2?NF5+N+NO3 OF2O2F2OFO3F2O4F2?OF4 F2 Ne NaF MgF2 AlFAlF3 SiF4 P2F4PF3PF5+PO4 S2F2SF2S2F4SF3SF4S2F10SF6+SO4 ClFClF3ClF5 ?ArF2?ArF4 KF CaFCaF2 ScF3 TiF2TiF3TiF4 VF2VF3VF4VF5 CrF2CrF3CrF4CrF5?CrF6 MnF2MnF3MnF4?MnF5 FeF2FeF3FeF4 CoF2 CoF3 CoF4 NiF2NiF3NiF4 CuFCuF2?CuF3 ZnF2 GaF2GaF3 GeF2GeF4 AsF3AsF5 Se2F2SeF4SeF6+SeO3 BrFBrF3BrF5 KrF2?KrF4?KrF6 RbF SrFSrF2 YF3 ZrF2ZrF3ZrF4 NbF4NbF5 MoF4MoF5MoF6 TcF4TcF5 TcF6 RuF3RuF4RuF5RuF6 RhF3RhF4RhF5RhF6 PdF2Pd[PdF6]PdF4?PdF6 Ag2FAgFAgF2AgF3 CdF2 InFInF3 SnF2SnF4 SbF3SbF5 TeF4?Te2F10TeF6+TeO3 IFIF3IF5IF7+IO3 XeF2XeF4XeF6?XeF8 CsF BaF2   LuF3 HfF4 TaF5 WF4WF5WF6 ReF4ReF5ReF6ReF7 OsF4OsF5OsF6?OsF7?OsF8 IrF2IrF3IrF4IrF5IrF6 PtF2Pt[PtF6]PtF4PtF5PtF6 AuFAuF3Au2F10?AuF6AuF5•F2 Hg2F2HgF2?HgF4 TlFTlF3 PbF2PbF4 BiF3BiF5 PoF2PoF4PoF6 AtF?AtF3?AtF5 RnF2?RnF4?RnF6 FrF RaF2   LrF3 Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og ↓ LaF3 CeF3CeF4 PrF3 PrF4 NdF2 NdF3 NdF4 PmF3 SmF SmF2 SmF3 EuF2 EuF3 GdF3 TbF3 TbF4 DyF2 DyF3 DyF4 HoF3 ErF3 TmF2 TmF3 YbF2 YbF3 AcF3 ThF2ThF3ThF4 PaF4PaF5 UF3UF4UF5UF6 NpF3NpF4NpF5NpF6 PuF3PuF4PuF5PuF6 AmF2AmF3AmF4?AmF6 CmF3CmF4 ?CmF6 BkF3 BkF4 CfF3 CfF4 EsF3 EsF4?EsF6 Fm MdF3 No
PF−6, AsF−6, SbF−6 compounds	AgPF6 KAsF6 LiAsF6 NaAsF6 HPF6 HSbF6 NH4PF6 LiSbF6 KPF6 KSbF6 LiPF6 NaPF6 NaSbF6 TlPF6
AlF2−5, AlF3−6 compounds	(NH4)3[AlF6] Cs2AlF5 Li3AlF6 K3AlF6 Na3AlF6
chlorides, bromides, iodides and pseudohalogenides	BaClF SiIBrClF BrSO3F Br(SO3F)3 CFN ClFO2 PbFBr PbFCl SrFCl
SiF2−6, GeF2−6 compounds	BaSiF6 BaGeF6 (NH4)2SiF6 Na2[SiF6] K2[SiF6] Li2GeF6 Li2SiF6
Oxyfluorides	AcOF C7H5FO BrOF3 BrO2F ErOF HoOF BrO3F NdOF NpO2F2 LaOF SmOF TbOF ThOF2 VOF3 TcO3F PrOF PuOF PuO2F2 UO2F2 WOF4 C2F4O YOF ClOF3 ClO2F3
Organofluorides	CBrF3 CBr2F2 CBr3F CClF3 CCl2F2 CCl3F CF2O CF3I CHF3 CH2F2 CH3F C2Cl3F3 C2H3F C6H5F C7H5F3 C15F33N C3H5F C6H11F
with transition metal, lanthanide, actinide, ammonium	VOF3 CrOF4 CrF2O2 NH4F (NH4)3CrF6 (NH4)3GaF6 (NH4)2GeF6 (NH4)3FeF6 (NH4)3InF6 NH4NbF6 (NH4)2SnF6 NH4TaF6 (NH4)3VF6 (NH4)2ZrF6 CsXeF7 Li2SnF6 Li2TiF6 LiWF6 Li2ZrF6 K2TiF6 Rb2TiF6 Na2TiF6 Na2ZrF6 K2NbF7 K2TaF7 K2ZrF6 UO2F2
nitric acids	FNO FNO2 FNO3
bifluorides	KHF2 NaHF2 NH4HF2
thionyl, phosphoryl, and iodosyl	FN3O2S F2OS3 F2OS F3OP PSF3 IOF3 IO3F F2O6S2 F2O5S2 FClO5S2 ISO3F IOF5 IO2F IO2F3 I3SO3F S3O8F2
Chemical formulas