Lithium tetrafluoroborate

Lithium tetrafluoroborate

Names
IUPAC name Lithium tetrafluoroborate
Other names Borate(1-), tetrafluoro-, lithium
Identifiers
CAS Number	14283-07-9 Y
ChemSpider	3504162 Y
Jmol 3D model	Interactive image
PubChem	4298216
InChI InChI=1S/BF4.Li/c2-1(3,4)5;/q-1;+1 Y Key: UFXJWFBILHTTET-UHFFFAOYSA-N Y InChI=1/BF4.Li/c2-1(3,4)5;/q-1;+1 Key: UFXJWFBILHTTET-UHFFFAOYAL
SMILES [Li+].F[B-](F)(F)F
Properties
Chemical formula	LiBF4
Molar mass	93.746 g/mol
Appearance	White/grey crystalline solid
Odor	odorless
Density	0.852 g/cm3 solid
Melting point	296.5 °C (565.7 °F; 569.6 K)
Boiling point	decomposes
Solubility in water	Very soluble
Vapor pressure	{{{value}}}
Related compounds
Other anions	Tetrafluoroborate,
Related compounds	Nitrosyl tetrafluoroborate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Lithium tetrafluoroborate is an inorganic compound with the formula LiBF₄. It is a white crystalline powder. It has been extensively tested for use in commercial secondary batteries, an application that exploits its high solubility in nonpolar solvents.

Applications

Although BF₄⁻ has high ionic mobility, solutions of its Li⁺ salt are less conductive than other less associated salts. As an electrolyte in Lithium-ion batteries, LiBF₄ offers some advantages relative to the more common LiPF₆. It exhibits greater thermal stability and moisture tolerance. For example LiBF₄ can tolerate a moisture content up to 620 ppm at room temperature whereas LiPF₆ readily hydrolyzes into toxic POF₃ and HF gases, often destroying the battery's electrode materials. Disadvantages of the electrolyte include a relatively low conductivity and difficulties forming a stable solid electrolyte interface with graphite electrodes.

Thermal stability

Because LiBF₄ and other alkali-metal salts thermally decompose to evolve boron trifluoride, the salt is commonly used as a convenient source of the chemical at the laboratory scale:

LiBF₄ → LiF + BF₃

Production

LiBF₄ is a byproduct in the industrial synthesis of diborane:

8 BF₃ + 6 LiH → B₂H₆ + 6 LiBF₄

LiBF₄ can also be synthesized from LiF and BF₃ in an appropriate solvent that is resistant to fluorination by BF₃ (e.g. HF, BrF₃, or liquified SO₂):

LiF + BF₃ → LiBF₄