Contents

Bifluoride

Bifluoride

Names
Other names Hydrogen(difluoride) anion Bifluoride anion Hydrogen difluoride anion
Identifiers
CAS Number	18130-74-0 Y
3D model (JSmol)	Interactive image
ChemSpider	35308425 N
CompTox Dashboard (EPA)	DTXSID70274195
InChI InChI=1S/F2H/c1-3-2/q-1 Key: LJRMFMQHZAVYNS-UHFFFAOYSA-N
SMILES F[H][F-]
Properties
Chemical formula	[HF2]−
Molar mass	39.005 g·mol−1
Conjugate acid	Hydrogen fluoride
Conjugate base	Fluoride
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

The bifluoride ion is an inorganic anion with the chemical formula [HF₂]⁻. The anion is colorless. Salts of bifluoride are commonly encountered in the reactions of fluoride salts with hydrofluoric acid. The commercial production of fluorine involves electrolysis of bifluoride salts.

Structure and bonding[edit]

The bifluoride ion has a linear, centrosymmetric structure (D_∞h symmetry), with an F−H bond length of 114 pm.^[1] The bond strength is estimated to be greater than 155 kJ/mol.^[2]Inmolecular orbital theory, the atoms are modeled to be held together by a 3-center 4-electron bond (symmetrical hydrogen bond).^[3]

Reactions[edit]

Salts, such as potassium bifluoride and ammonium bifluoride are produced by treating fluoride salts with hydrofluoric acid:

M⁺F⁻ + HF → M⁺[HF₂]⁻, where M⁺ = K⁺or[NH₄]⁺

Potassium bifluoride binds a second equivalent of HF:^[4]

K[HF₂] + HF → K[H₂F₃]

Heating these salts releases anhydrous HF.

References[edit]

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