Materials Data on MgCu2SiSe4 by Materials Project
Cu2MgSiSe4 is Stannite-like structured and crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. Mg2+ is bonded to four Se2- atoms to form MgSe4 tetrahedra that share corners with four equivalent SiSe4 tetrahedra and corners with eight equivalent CuSe4 tetrahedra. There are a spread of Mg–Se bond distances ranging from 2.57–2.63 Å. Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent MgSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, and corners with four equivalent SiSe4 tetrahedra. There are three shorter (2.43 Å) and one longer (2.46 Å) Cu–Se bond lengths. Si4+ is bonded to four Se2- atoms to form SiSe4 tetrahedra that share corners with four equivalent MgSe4 tetrahedra and corners with eight equivalent CuSe4 tetrahedra. All Si–Se bond lengths are 2.32 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Mg2+, two equivalent Cu1+, and one Si4+ atom to form corner-sharing SeMgCu2Si tetrahedra. In the second Se2- site, Se2- is bonded to one Mg2+, two equivalent Cu1+, and one Si4+ atom to form corner-sharing SeMgCu2Si tetrahedra. In the third Se2- site, Se2- is bonded to one Mg2+, two equivalent Cu1+, and one Si4+ atom to form corner-sharing SeMgCu2Si tetrahedra.