Names | |
---|---|
IUPAC name
barium(2+); dioxido(oxo)phosphanium
| |
Identifiers | |
3D model (JSmol)
|
|
ChemSpider | |
ECHA InfoCard | 100.033.951 |
EC Number |
|
PubChem CID
|
|
CompTox Dashboard (EPA)
|
|
| |
| |
Properties | |
Ba(PO3)2 | |
Molar mass | 295.27 g/mol |
Appearance | Powder[1] |
Density | 3.63 g/cm3 |
Melting point | 1,560[2] °C (2,840 °F; 1,830 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Barium metaphosphate is an inorganic substance with the molecular formula Ba(PO3)2. It is a colourless solid that is insoluble in water, though is soluble in acidic solutions through "slow dissolution".[3] X-ray crystallography shows that this material is composed of Ba2+ cations attached to a polyphosphate ((PO3−)n) anion.[4] A number of hydrated forms are known which are actually cyclic metaphosphates, Ba2(P4O12)·3.5H2O, Ba3(P3O9)2·6H2O.[citation needed]
Barium metaphosphate can be prepared by the reaction of barium carbonate with metaphosphoric acid:[citation needed]
or alternatively by the aqueous reaction of barium chloride and sodium metaphosphate:[citation needed] BaCl2(aq) + 2NaPO3(aq) → Ba(PO3)2 + 2NaCl
The combination of sodium and barium polyphosphate forms a low-melting glass with a high coefficient of thermal expansion. The melting point of the glass increases with barium content. This glass makes seals with low melting metals like aluminium (melting point 650 °C). Normal borosilicate glasses soften above the melting point of aluminium. This mixture is prepared by heating a mixture of diammonium phosphate, sodium carbonate, and barium carbonate.[5]