Materials Data on Mg3Cu3(AsO4)4 by Materials Project
Mg3Cu3(AsO4)4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mg–O bond distances ranging from 1.98–2.60 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six AsO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 2.00–2.23 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five AsO4 tetrahedra and an edgeedge with one MgO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.93–2.29 Å. In the second Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.93 Å) and two longer (1.95 Å) Cu–O bond length. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with three equivalent CuO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 46–61°. There are a spread of As–O bond distances ranging from 1.68–1.76 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with two equivalent CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 54°. There are a spread of As–O bond distances ranging from 1.67–1.79 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, two Cu2+, and one As5+ atom. In the second O2- site, O2- is bonded to two Mg2+, one Cu2+, and one As5+ atom to form distorted corner-sharing OMg2CuAs tetrahedra. In the third O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+, one Cu2+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+, one Cu2+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mg2+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Cu2+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Cu2+, and one As5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mg2+ and one As5+ atom.