DOI: 10.17188/1651695
title: Materials Data on Mg12Si4H2O21 by Materials Project

description: Mg12Si4O19(OH)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are thirteen 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 and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.05–2.17 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with five MgO6 octahedra, corners with three SiO4 tetrahedra, edges with five MgO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 1–58°. There are a spread of Mg–O bond distances ranging from 2.00–2.28 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent SiO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–21°. There are two shorter (2.13 Å) and four longer (2.16 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–18°. There are a spread of Mg–O bond distances ranging from 2.07–2.14 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two SiO4 tetrahedra, edges with two equivalent SiO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 8–17°. There are a spread of Mg–O bond distances ranging from 2.08–2.18 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two MgO6 octahedra, corners with four SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with five MgO6 octahedra. The corner-sharing octahedra tilt angles range from 15–17°. There are a spread of Mg–O bond distances ranging from 2.12–2.16 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–16°. There are a spread of Mg–O bond distances ranging from 2.07–2.15 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with five MgO6 octahedra, a cornercorner with one SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, edges with six MgO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 1–62°. There are a spread of Mg–O bond distances ranging from 2.08–2.16 Å. In the ninth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one SiO6 octahedra, corners with four MgO6 octahedra, a cornercorner with one SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with six MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–59°. There are a spread of Mg–O bond distances ranging from 2.03–2.30 Å. In the tenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six MgO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with four MgO6 octahedra. The corner-sharing octahedra tilt angles range from 17–61°. There are a spread of Mg–O bond distances ranging from 2.00–2.30 Å. In the eleventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with five MgO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with five MgO6 octahedra. The corner-sharing octahedra tilt angles range from 8–62°. There are a spread of Mg–O bond distances ranging from 2.00–2.25 Å. In the twelfth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with five MgO6 octahedra, a cornercorner with one SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, edges with six MgO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–61°. There are a spread of Mg–O bond distances ranging from 2.08–2.15 Å. In the thirteenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with five MgO6 octahedra, corners with two SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with five MgO6 octahedra. The corner-sharing octahedra tilt angles range from 10–59°. There are a spread of Mg–O bond distances ranging from 2.00–2.21 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share a cornercorner with one MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of Si–O bond distances ranging from 1.81–1.91 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six MgO6 octahedra and edges with three MgO6 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There is one shorter (1.63 Å) and three longer (1.65 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with twelve MgO6 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Si–O bond distances ranging from 1.67–1.69 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There is three shorter (1.67 Å) and one longer (1.68 Å) Si–O bond length. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are twenty-one inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ and one Si4+ atom to form OMg5Si octahedra that share a cornercorner with one OMg4Si square pyramid, an edgeedge with one OMg5Si octahedra, and edges with six OMg4Si square pyramids. In the second O2- site, O2- is bonded to four Mg2+ and one Si4+ atom to form OMg4Si square pyramids that share a cornercorner with one OMg5Si octahedra, corners with two OMg4Si square pyramids, edges with two equivalent OMg6 octahedra, and edges with four OMg4Si square pyramids. The corner-sharing octahedral tilt angles are 1°. In the third O2- site, O2- is bonded to four Mg2+ and one Si4+ atom to form OMg4Si square pyramids that share corners with two OMg4Si square pyramids, edges with three OMg5Si octahedra, and edges with three OMg4Si square pyramids. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mg2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to three Mg2+ and one H1+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three Mg2+ and one H1+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the eighteenth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share a cornercorner with one OMg6 octahedra and edges with six OMg4Si square pyramids. The corner-sharing octahedral tilt angles are 0°. In the nineteenth O2- site, O2- is bonded to four Mg2+ and one Si4+ atom to form OMg4Si square pyramids that share corners with three OMg4Si square pyramids, edges with three OMg5Si octahedra, and edges with three OMg4Si square pyramids. In the twentieth O2- site, O2- is bonded to four Mg2+ and one Si4+ atom to form OMg4Si square pyramids that share a cornercorner with one OMg4Si square pyramid, edges with two OMg5Si octahedra, and edges with three OMg4Si square pyramids. In the twenty-first O2- site, O2- is bonded to four Mg2+ and one Si4+ atom to form distorted OMg4Si square pyramids that share corners with two OMg4Si square pyramids, edges with two equivalent OMg5Si octahedra, and edges with three OMg4Si square pyramids.