Preparation and crystal structure of the copper silicon polyphosphide Cu4SiP8

Article abstract of DOI:10.1002/zaac.19966220109

The new compound Cu₄SiP₈ was prepared by solid state reaction of the elemental components. It crystallizes with a new structure type, which was determined from single-crystal X-ray diffractometer data: I4₁/a, a = 1218.6(2)pm, c = 573.2(2) pm, Z = 8, R = 0.023 for 970 structure factors and 31 variable parameters. Tetrahedral SiP₄ groups are linked via additional phosphorus atoms to a three-dimensionally infinite silicon phosphorus network, accommodating Cu₂ pairs with octahedral phosphorus coordination as is known for the closely related structure of CuP₂. Using oxidation numbers the compound may be rationalized by the formula (Cu⁺¹)₄Si⁺⁴(P⁰)₄(P ^-2)₄ in agreement with the Zintl-Klemm concept. Johann Ambrosius Barth 1996.