The layered polyphosphide Ag_3.73(4)Zn_2.27(4)P₁₆

The silver zinc hexa­deca­phosphide Ag_3.73(4)Zn_2.27(4)P₁₆ is the first polyphosphide in the ternary system Ag/Zn/P. It was synthesized from stoichiometric mixtures of Ag, Zn and P in the molar ratio 4:2:16, using AgI as a mineralizing agent in a gas-phase-assisted reaction. Ag_3.73(4)Zn_2.27(4)P₁₆ crystallizes in the Cu₅InP₁₆ structure type. The asymmetric unit contains two Ag/Zn sites with mixed occupancies and four P sites. One of the Ag/Zn sites is located on a twofold rotation axis. The polyanionic [P₁₆]-substructure consists of corrugated six-membered rings that are connected into a layer via the 1-, 2-, 4- and 5-positions of the rings by a bridging P atom in each case. The layers extend parallel to the bc plane and are stacked along the a axis. Both Ag/Zn sites are tetra­hedrally coordinated by P atoms.