KSi2P3: A new layered phosphidopolysilicate (IV)

•A new ternary phosphidopolysilicate (IV), KSi2P3, has been synthesized.•The SiP4 tetrahedra are connected to form two-dimensional layer [Si2P3]−∞2.•The two-dimensional layers are separated by K+ cations.•KSi2P3 is a semiconductor with band gap of 1.72 eV.

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) Å, b=10.1382(5) Å, c=21.1181(10) Å, 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 [Si2P3]−∞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.

Graphical abstractKSi2P3 contains two-dimensional layer [Si2P3]−∞2 separated by K+ cations.Figure optionsDownload full-size imageDownload as PowerPoint slide