Barium Metaphosphate

Barium metaphosphate is a chemical compound with the formula Ba(PO3)2. It is a white, crystalline solid that is insoluble in water and has a high melting point of approximately 1240°C.

Barium metaphosphate is primarily used as a material for the production of optical glasses, ceramics, and other specialty materials. It is known for its excellent thermal stability and resistance to chemical attack, which makes it useful in high-temperature applications.

In terms of its crystal structure, barium metaphosphate belongs to the monoclinic crystal system and has space group C2/c. Its unit cell contains four formula units and has dimensions of a = 12.24 Å, b = 8.41 Å, c = 6.63 Å, and β = 100.7°.

Barium metaphosphate exhibits an interesting phenomenon known as "negative thermal expansion," where it contracts upon heating instead of expanding like most materials do. This property makes it useful in certain specialized applications where precise dimensional stability is required.

Overall, barium metaphosphate is a versatile and important compound with many useful properties, particularly in the field of materials science and engineering.