One-Dimensional [P15]− Tubes in Layered Semiconducting AgP15

AgP15 was synthesized from the elements via a short-way transport reaction following the mineralizer concept. The needle-shaped crystals were characterized by single-crystal and powder X-ray diffraction. It crystallizes triclinically in space group P1̅ with cell parameters of a = 6.937(1) Å, b = 9.000(1) Å, c = 11.103(2) Å, α = 99.95(1)°, β = 99.61(1)°, and γ = 105.980(9)°. AgP15 exhibits a tubular phosphorus substructure related but neither isotypic nor isostructural to the alkaline phosphides MP15 (M = Li–Rb). The thermal properties, electronic structure, and experimental band gap of this new semiconductor have been determined. Finally, Raman spectra of AgP15 and selected alkaline-metal polyphosphides MP15 have been measured and interpreted. AgP15 represents the first transition-metal representative of this class of materials.