Materials Data on Na2Mg5(Si2O5)6 by Materials Project

Na2Mg5(Si2O5)6 crystallizes in the hexagonal P-62c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted trigonal planar geometry to nine O2- atoms. There are three shorter (2.48 Å) and six longer (3.03 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are six shorter (3.06 Å) and six longer (3.07 Å) Na–O bond lengths. There are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra. There are three shorter (2.08 Å) and three longer (2.14 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.96 Å) and two longer (1.98 Å) Mg–O bond length. 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 three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, two Mg2+, and one Si4+ atom.