|Molar mass||295.27 g/mol|
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. X-ray crystallography shows that this material is composed of Ba2+ cations attached to a polyphosphate ((PO3−)n) anion. A number of hydrated forms are known which are actually cyclic metaphosphates, Ba2(P4O12)·3.5H2O, Ba3(P3O9)2·6H2O.
- BaCO3 + 2HPO3 → Ba(PO3)2 +CO2 +H2O
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.
- "Form of barium metaphosphate" Grenier, Jean C.; Martin, Claude M.; Durif, Andre; Tran Qui Duc; Guitel, J. C. Bulletin de la Societe Francaise de Mineralogie et de Cristallographie (1967), vol. 90, 24-31.
- Ropp, Richard (2012). Encyclopedia of the Alkaline Earth Compounds. Newnes. p. 76. ISBN 0444595538.
- Wilder Jr., J.A. "Glasses and glass ceramics for sealing to aluminum alloys" Journal of Non-Crystalline Solids Volume 38-39, Issue PART 2, May 1980, Pages 879-884. Hart, Patricia E.; Mesko, Melissa G.; Shelby, James E. "Crystallization and phase equilibrium in the sodium barium metaphosphate system" Journal of Non-Crystalline Solids (2000), 263&264, 305-311. doi:10.1016/S0022-3093(99)00642-0
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