Barium phosphate

Not to be confused with Barium metaphosphate.

Barium phosphate, also known as barium orthophosphate, is an inorganic phosphate of barium with the molecular formula Ba₃(PO₄)₂. It is usually found as a white, odorless powder which is insoluble in water.^[1]

Barium phosphate

Names
IUPAC name Barium phosphate
Other names Barium orthophosphate
Identifiers
CAS Number	13517-08-3
3D model (JSmol)	Interactive image
ChemSpider	145305
ECHA InfoCard	100.033.491
EC Number	236-856-9
PubChem CID	165803
CompTox Dashboard (EPA)	DTXSID20889612
InChI InChI=1S/3Ba.2H3O4P/c;;;2*1-5(2,3)4/h;;;2*(H3,1,2,3,4)/q3*+2;;/p-6 Key: WAKZZMMCDILMEF-UHFFFAOYSA-H
SMILES [O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[Ba+2].[Ba+2].[Ba+2]
Properties
Chemical formula	Ba3(PO4)2
Molar mass	601.9 g/mol
Appearance	Powder
Structure
Crystal structure	Rhombohedral
Space group	R3m
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H332
Precautionary statements	P261, P264, P270, P271, P301+P317, P304+P340, P317, P330, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

The general chemical reaction for the synthesis of barium phosphate powder, using the sol-gel process, is:^[2]

3 Ba(NO₃)₂ + 2 NH₄H₂PO₄ → Ba₃(PO₄)₂ + 2 NH₄NO₃ + 4 HNO₃

Barium phosphate is formed as a precipitate.

Structure

Its crystal structure is rhombohedral with a space group of R3m, identical to that of strontium phosphate.^[3]

Properties

Barium phosphate exhibits properties such as high refractive index, low melting point, low glass transition temperature, high transparency to ultraviolet light, and high thermal expansion coefficient.^[4]

Applications

Barium phosphate finds uses in industrial applications, including optical applications like preparation of glasses with special properties for pulsed lasers, and preparation of solders for glass to glass bonding. It can also be used in development of hydrogen / fuel sensors.^[4]

See also

• Barium metaphosphate