KSi2P3: A new layered phosphidopolysilicate (IV)

Abstract

Abstract A new ternary phosphidopolysilicate (IV), KSi2P3, has been synthesized by high temperature solid state reaction. The compound crystallizes in a new structure type in the monoclinic space group C2/c with a=10.1327(5) A, b=10.1382(5) A, c=21.1181(10) A, β=96.88(0)°, and Z=8. In the structure, all SiP4 tetrahedra are connected with each other by corner-sharing P atoms to form [ Si 2 P 3 ] − ∞ 2 layers, which are stacked along c direction and separated by K+ cations. The two-dimensional structure of KSi2P3 contrasts with those of the two known members in the ternary A/Si/P (A=alkali metal) system, namely Na5SiP3 (zero-dimensional) and K2SiP2 (one-dimensional), which contains less amount of Si. The band gap deduced from UV–vis–IR diffuse reflectance spectrum is 1.72 eV.