Materials Data on Ca2Mg5Si8(O11F)2 by Materials Project
Ca2Mg5Si8(O11F)2 is Esseneite-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.80 Å. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- and two equivalent F1- atoms to form MgO4F2 octahedra that share corners with four SiO4 tetrahedra and edges with five MgO4F2 octahedra. There are two shorter (2.08 Å) and two longer (2.09 Å) Mg–O bond lengths. Both Mg–F bond lengths are 2.08 Å. In the second Mg2+ site, Mg2+ is bonded to four equivalent O2- and two equivalent F1- atoms to form MgO4F2 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with six MgO4F2 octahedra. All Mg–O bond lengths are 2.08 Å. Both Mg–F bond lengths are 2.04 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with three MgO4F2 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.18 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO4F2 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is two shorter (1.63 Å) and two longer (1.65 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO4F2 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–57°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. F1- is bonded in a distorted trigonal non-coplanar geometry to three Mg2+ atoms.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). LBNL Materials Project
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Contributing Organization:
- MIT; UC Berkeley; Duke; U Louvain
- DOE Contract Number:
- AC02-05CH11231; EDCBEE
- OSTI ID:
- 1269945
- Report Number(s):
- mp-557662
- Resource Relation:
- Related Information: https://materialsproject.org/citing
- Country of Publication:
- United States
- Language:
- English
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