Materials Data on Ca2Mg5Si8(HO12)2 by Materials Project

Dataset · Sat May 02 04:00:00 EDT 2020

DOI:https://doi.org/10.17188/1699311· OSTI ID:1699311

Ca2Mg5Si8O22(OH)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 2.34–2.85 Å. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.09–2.12 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with three MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.16 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with six MgO6 octahedra. There are two shorter (2.07 Å) and four longer (2.11 Å) Mg–O bond lengths. 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 MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–58°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form a mixture of distorted corner and edge-sharing OMg3Si trigonal pyramids. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three Mg2+ and one H1+ atom. 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 distorted bent 150 degrees geometry to one Ca2+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.

• Research Organization: LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Contributing Organization: The Materials Project; MIT; UC Berkeley; Duke; U Louvain
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1699311
• Report Number(s): mp-1196550
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Ca-H-Mg-O-Si
Ca2Mg5Si8(HO12)2
crystal structure