Materials Data on Mg3(AsO4)2 by Materials Project
Mg3(AsO4)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are nine inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.03–2.34 Å. In the second Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 trigonal bipyramids that share a cornercorner with one MgO5 trigonal bipyramid, an edgeedge with one AsO6 octahedra, and an edgeedge with one MgO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 2.01–2.16 Å. In the third Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted corner-sharing MgO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 1.94–2.04 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Mg–O bond distances ranging from 2.01–2.52 Å. In the fifth 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 2.13–2.53 Å. In the sixth Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted edge-sharing MgO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 1.99–2.29 Å. In the seventh Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 tetrahedra that share a cornercorner with one AsO6 octahedra and a cornercorner with one MgO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 10°. There are a spread of Mg–O bond distances ranging from 1.92–2.71 Å. In the eighth Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 tetrahedra that share an edgeedge with one AsO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.92–2.39 Å. In the ninth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 1.94–2.17 Å. There are six inequivalent As5+ sites. In the first As5+ site, As5+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.79–1.85 Å. In the second As5+ site, As5+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.76–1.91 Å. In the third As5+ site, As5+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.79–2.20 Å. In the fourth As5+ site, As5+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of As–O bond distances ranging from 1.72–2.36 Å. In the fifth As5+ site, As5+ is bonded to six O2- atoms to form distorted AsO6 octahedra that share a cornercorner with one MgO5 tetrahedra, an edgeedge with one MgO5 tetrahedra, and an edgeedge with one MgO5 trigonal bipyramid. There are a spread of As–O bond distances ranging from 1.82–2.25 Å. In the sixth As5+ site, As5+ is bonded in a distorted water-like geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.74–2.49 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Mg2+ and one As5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+ and two As5+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to three Mg2+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one As5+ and one O2- atom. The O–O bond length is 1.50 Å. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one As5+, and one O2- atom. The O–O bond length is 1.50 Å. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one O2- atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Mg2+, one As5+, and one O2- atom. The O–O bond length is 1.50 Å. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and one O2- atom. In the ninth O2- site, O2- is bonded in a trigonal planar geometry to two Mg2+ and one As5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one As5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and one As5+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to two Mg2+ and one As5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one As5+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one As5+, and one O2- atom. The O–O bond length is 1.50 Å. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one O2- atom. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one O2- atom. The O–O bond length is 1.50 Å. In the eighteenth O2- site, O2- is bonded in a trigonal planar geometry to two Mg2+ and one As5+ atom. In the nineteenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to two Mg2+ and one As5+ atom. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+ and two As5+ atoms. In the twenty-first O2- site, O2- is bonded in a 1-coordinate geometry to one Mg2+, one As5+, and one O2- atom. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and one As5+ atom. In the twenty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one As5+ atom. In the twenty-fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Mg2+, one As5+, and one O2- atom.