Materials Data on MgCu2(SiO3)4 by Materials Project
MgCu2(SiO3)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.30 Å. Cu3+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.82–1.89 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–55°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Cu3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cu3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cu3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms.