Materials Data on Mg3Al2(SiO4)3 by Materials Project
Mg3Al2Si3O12 crystallizes in the cubic Ia-3d space group. The structure is three-dimensional. Mg2+ is bonded in a distorted body-centered cubic geometry to eight equivalent O2- atoms. There are four shorter (2.22 Å) and four longer (2.37 Å) Mg–O bond lengths. Al3+ is bonded to six equivalent O2- atoms to form AlO6 octahedra that share corners with six equivalent SiO4 tetrahedra. All Al–O bond lengths are 1.90 Å. Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. All Si–O bond lengths are 1.65 Å. O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+, one Al3+, and one Si4+ atom.