Lithium phosphate

Not to be confused with Lithium iron phosphate.

Lithium phosphate is a phosphate salt of lithium, with the molecular formula Li₃PO₄.^[3] It is a white solid slightly soluble in water.

Lithium phosphate

Names
IUPAC name Lithium phosphate
Other names Trilithium phosphate
Identifiers
CAS Number	10377-52-3
3D model (JSmol)	Interactive image
ChemSpider	145361
ECHA InfoCard	100.030.736
EC Number	233-823-0
PubChem CID	165867
UNII	2QM4K05Q74
CompTox Dashboard (EPA)	DTXSID60889590
InChI InChI=1S/3Li.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3 Key: TWQULNDIKKJZPH-UHFFFAOYSA-K
SMILES [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O
Properties
Chemical formula	Li3PO4
Molar mass	115.794 g/mol
Appearance	White powder
Density	2.46 g/cm3[1]
Melting point	1,205 °C (2,201 °F; 1,478 K)[1]
Solubility in water	0.027 g/100 mL (25 °C)[1]
Structure[2]
Crystal structure	Orthorhombic
Space group	Pmn21
Lattice constant	a = 6.115, b = 5.239, c = 4.855
Coordination geometry	Tetrahederal (at all atoms)
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	-2095.8 kJ/mol[1]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
NFPA 704 (fire diamond)	2 0 0
Related compounds
Other cations	Trisodium phosphate Tripotassium phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

It is primarily used in the production of lithium iron phosphate (LiFePO₄) for making lithium-ion batteries.^[3]

Synthesis and structure

Trilithium phosphate can be produced by the neutralization of lithium carbonate using phosphoric acid:^[1]

3 Li₂CO₃ + 2 H₃PO₄ → 2 Li₃PO₄ + 3 H₂O + 3 CO₂

The low-temperature polymorph (β-Li₃PO₄) crystallizes as an orthorhombic crystal with the space group Pmn2₁. If heated to above 500 °C, it converts to another polymorph, γ-Li₃PO₄.^[4]

Hazards

Health

Large doses of lithium phosphate may cause dizziness, and sometimes, kidney damage. According to some reports, dehydration, weight loss, and thyroid disturbances can occur due to high exposure of lithium ions. Nervous system defects, including slurred speech, blurred vision, sensory loss, and convulsions may also occur.^[3]

See also

• Lithium iron phosphate
• Lithium-ion battery