Tin triphosphide

Tin triphosphide is a binary inorganic compound of tin metal and phosphorus with the chemical formula SnP3.

Structure
X-ray crystallography reveals that tin triphosphide is not a triphosphide. It is a hexaphosphide, with P66- rings. These ruffled P6 rings form three short (2.66 Å) and three long (2.95 Å) Sn-P bonds. The result is that Sn(II) adopts highly distorted octahedral geometry. The structure of tin triphosphide resembles that of gray arsenic, which also features corrugated, linked six-membered (As6) rings, wherein each arsenic atom has a highly distorted octahedral geometry. Germanium triphosphide and tin triphosphide are similar structurally as well.

Tin triphosphide forms triclinic crystals, spatial group R3m with six formula units in a unit cell of dimensions a = 7.378 Å and c = 10.512 Å.

Preparation and occurrence
Tin triphosphide can be formed from the fusion of stoichiometric amounts of both elements at 580 °C:
 * Sn + 3P -> SnP3

SnP3 has been evaluated for use in energy storage devices.

Related compounds

 * SnP, which has the sodium chloride structure.
 * Sn4P3