Phosphide
In chemistry, a phosphide is a compound containing the P3− ion or its equivalent. Many different phosphides are known, with widely differing structures. Most commonly encountered on the binary phosphides, i.e. those materials consisting only of phosphorus and a less electronegative element. Numerous are polyphosphides, which are solids consisting of anionic chains or clusters of phosphorus. Phosphides are known with the majority of less electronegative elements with the exception of Hg, Pb, Sb, Bi, Te, and Po. Finally, some phosphides are molecular.
Examples of group 1 include Na
3P. Notable examples include aluminium phosphide (AlP) and calcium phosphide (Ca3P2), which used as pesticides, exploiting their tendency to release toxic phosphine upon hydrolysis. Magnesium phosphide (Mg3P2) also is moisture sensitive. Indium phosphide (InP) and GaP are used as a semi-conductors, often in combination of related arsenides.Copper phosphide (Cu3P) illustrates a rare stoichiometry for a phosphide. These species are insoluble in all solvents - they are 3-dimensional solid state polymers. For those with electropositive metals, the materials hydrolyze:
Polyphosphides contain P-P bonds. The simplest polyphosphides contain P4−
2 ions;. Others contain the cluster P3−
11 ions and polymeric chain anions (e.g. the helical (P−
)
n ion) and complex sheet or 3-D anions. The range of structures is extensive. Potassium has nine phosphides: K3P, K4P3, K5P4, KP, K4P6, K3P7, K3P11, KP10.3, KP15. Eight mono- and polyphosphides of nickel has eight (Ni3P, Ni5P2, Ni12P5, Ni2P, Ni5P4, NiP, NiP2, NiP3).
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