Close up on the structure of SnP3, highlighting the bonding around P (violet) and Sn (gray).
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.[2][3]
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.[4]
^Jacobson, Carl Alfred; Hampel, Clifford A. (1946). Encyclopedia of Chemical Reactions. Reinhold Publishing Corporation. p. 15. Retrieved 28 March 2024.
^Donohue, Paul C. (1970). "Synthesis, Structure, and Superconducting Properties of New High-Pressure Forms of Tin Phosphide". Inorganic Chemistry. 9 (2): 335–337. doi:10.1021/ic50084a032.