Lithium phosphate

Structural formula
General
Surname	Lithium phosphate
other names	Lithium orthophosphate Trilithium orthophosphate
Molecular formula	Li 3 PO 4
Brief description	colorless and odorless solid
External identifiers / databases
CAS number 10377-52-3 EC number 233-823-0 ECHA InfoCard 100.030.736 PubChem 165867 Wikidata Q426354
properties
Molar mass	115.79 g mol −1
Physical state	firmly
density	2.45 g cm −3 2.42 g cm −3 (high temperature form) 2.41 g cm −3
Melting point	837 ° C
solubility	heavy in water (0.39 g l −1 at 18 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302 P: 261-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Lithium phosphate is a chemical compound from the group of phosphates .

Occurrence

Lithium phosphate occurs naturally as a rare mineral, lithiophosphatite .

Extraction and presentation

Lithium phosphate can be obtained from alkaline (e.g. sodium hydroxide ) solutions to which a little disodium hydrogen phosphate Na ₂ HPO _{4 has been} added. When heated, lithium phosphate precipitates out as a white precipitate in the presence of Li ⁺ (other dissolved lithium salts, e.g. lithium chloride ):

${\displaystyle \mathrm {3\,Li^{+}+HPO_{4}^{2-}+OH^{-}\rightarrow Li_{3}PO_{4}\downarrow +H_{2}O} }$

It is also possible to obtain it by reacting an aqueous suspension of lithium carbonate with phosphoric acid and then heating it to boiling. There is also a high temperature form of trilithium phosphate which is stable at normal temperatures and which, at temperatures above the transition temperature of 502 ° C, e.g. B. can be crystallized from molten lithium chloride.

properties

Lithium phosphate is a colorless solid. It crystallizes orthorhombically with the lattice constants a = 6.12 Å , b = 10.53 Å and c = 4.93 Å with the space group Pmnb (space group no. 62, position 2) . It also occurs as the lithium phosphate hemihydrate Li ₃ PO ₄ · ½H ₂ O. The high temperature variant has a crystal structure with the space group Pcmn (no. 62, position 4) . There are also lithium metaphosphate LiPO ₃ ( monoclinic , space group Pn (No. 7, position 2) ), lithium polyphosphate (P ₂ O ₅ : Li ₂ O> 1), lithium dihydrogen phosphate LiH ₂ PO ₄ (orthorhombic, space group Pna 2 ₁ (no 33) ) and lithium dihydrogen diphosphate Li ₂ H ₂ P ₂ O ₇ .

use

Lithium phosphate can be used to detect lithium by precipitation reaction in an alkaline medium. It is still used as a component of certain enamels and as a polymer intermediate. It is also used to extract lithium iron phosphate for lithium iron phosphate batteries and doped with nitrogen as a lithium ion conductor.

Individual evidence

1. ↑ ^{a b} data sheet lithium phosphate from Sigma-Aldrich , accessed on January 26, 2019 ( PDF ).
2. ↑ ^{a b} Entry on lithium phosphate in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
3. ↑ ^{a b c} J. Zemann: The crystal structure of lithium phosphate, Li3PO4 . In: Acta Cryst. (1960). 13, 863-867 doi: 10.1107 / S0365110X60002132
4. ↑ ^{a b c d e} entry on lithium phosphates. In: Römpp Online . Georg Thieme Verlag, accessed on December 25, 2014.
5. ↑ ^{a b} fmclithium: Lithium Orthophosphine Tertiary (PDF; 208 kB)
6. ↑ Lithium phosphate data sheet at AlfaAesar, accessed on May 19, 2017 ( PDF )(JavaScript required) .
7. ↑ Mindat: Lithiophosphate
8. ↑ HL Buff: Short textbook of inorganic chemistry according to the newer views . 1868, p. 186 ( limited preview in Google Book search).
9. ↑ American Mineralogist Crystal Structure Database: lithiophosphate
10. ^ Karl-Heinz Lautenschläger, Werner Schröter and Andrea Wanninger: Taschenbuch der Chemie . 2005, ISBN 3-8171-1760-4 , pp. 662 ( limited preview in Google Book search).