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Title: Materials Data on Ca13Nb3(Si2O9)4 by Materials Project

Abstract

Ca13Nb3(Si2O9)4 is Esseneite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirteen inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two NbO6 octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Ca–O bond distances ranging from 2.33–2.49 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of Ca–O bond distances ranging from 2.29–2.59 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two NbO6 octahedra, corners with five SiO4 tetrahedra, and edges with two equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Ca–O bond distances ranging from 2.31–2.48 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atomsmore » to form CaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Ca–O bond distances ranging from 2.30–2.56 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five SiO4 tetrahedra, and edges with two equivalent CaO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Ca–O bond distances ranging from 2.35–2.48 Å. In the sixth Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.22–2.87 Å. In the seventh Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.21–2.77 Å. In the eighth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.86 Å. In the ninth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.87 Å. In the tenth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.84 Å. In the eleventh Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.87 Å. In the twelfth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.23–2.64 Å. In the thirteenth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.94 Å. There are three inequivalent Nb+4.67+ sites. In the first Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three CaO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the second Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one CaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Nb–O bond distances ranging from 1.89–2.30 Å. In the third Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two CaO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 59–64°. There are a spread of Nb–O bond distances ranging from 1.91–2.17 Å. There are eight 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 NbO6 octahedra, corners with four CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–66°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with four CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–78°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–65°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–67°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–61°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–72°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–67°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two CaO6 octahedra, corners with two NbO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–63°. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Si4+ atom. In the third O2- site, O2- is bonded to three Ca2+ and one Nb+4.67+ atom to form distorted OCa3Nb trigonal pyramids that share corners with three OCa3Si tetrahedra and an edgeedge with one OCa4 tetrahedra. In the fourth O2- site, O2- is bonded to three Ca2+ and one Nb+4.67+ atom to form distorted OCa3Nb tetrahedra that share corners with five OCa3Si tetrahedra and an edgeedge with one OCa2Nb2 tetrahedra. In the fifth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted OCa3Si tetrahedra that share corners with three OCa2Nb2 tetrahedra and a cornercorner with one OCa3Nb trigonal pyramid. In the sixth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted OCa3Si tetrahedra that share corners with two OCa2Nb2 tetrahedra and a cornercorner with one OCa3Nb trigonal pyramid. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the ninth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted corner-sharing OCa3Si tetrahedra. In the tenth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted OCa3Si tetrahedra that share corners with two OCa4 tetrahedra and a cornercorner with one OCa3Nb trigonal pyramid. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Nb+4.67+ atom. In the twelfth O2- site, O2- is bonded to two Ca2+ and two Nb+4.67+ atoms to form distorted OCa2Nb2 tetrahedra that share corners with four OCa3Nb tetrahedra and an edgeedge with one OCa2Nb2 tetrahedra. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the twenty-third O2- site, O2- is bonded to four Ca2+ atoms to form OCa4 tetrahedra that share corners with three OCa3Si tetrahedra and an edgeedge with one OCa3Nb trigonal pyramid. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Nb+4.67+ atom. In the twenty-fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Nb+4.67+ atom. In the twenty-sixth O2- site, O2- is bonded to two Ca2+ and two Nb+4.67+ atoms to form distorted OCa2Nb2 tetrahedra that share corners with two OCa3Si tetrahedra and edges with two OCa3Nb tetrahedra. In the twenty-seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ca2+ and two Si4+ atoms. In the thirtieth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two Si4+ atoms. In the thirty-first O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the thirty-second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom. In the thirty-third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ca2+ and one Si4+ atom. In the thirty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the thirty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom. In the thirty-sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom.« less

Authors:
Publication Date:
Other Number(s):
mp-1228717
DOE Contract Number:  
AC02-05CH11231; EDCBEE
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). LBNL Materials Project
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Collaborations:
MIT; UC Berkeley; Duke; U Louvain
Subject:
36 MATERIALS SCIENCE
Keywords:
crystal structure; Ca13Nb3(Si2O9)4; Ca-Nb-O-Si
OSTI Identifier:
1681582
DOI:
https://doi.org/10.17188/1681582

Citation Formats

The Materials Project. Materials Data on Ca13Nb3(Si2O9)4 by Materials Project. United States: N. p., 2020. Web. doi:10.17188/1681582.
The Materials Project. Materials Data on Ca13Nb3(Si2O9)4 by Materials Project. United States. doi:https://doi.org/10.17188/1681582
The Materials Project. 2020. "Materials Data on Ca13Nb3(Si2O9)4 by Materials Project". United States. doi:https://doi.org/10.17188/1681582. https://www.osti.gov/servlets/purl/1681582. Pub date:Thu Apr 30 00:00:00 EDT 2020
@article{osti_1681582,
title = {Materials Data on Ca13Nb3(Si2O9)4 by Materials Project},
author = {The Materials Project},
abstractNote = {Ca13Nb3(Si2O9)4 is Esseneite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirteen inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two NbO6 octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Ca–O bond distances ranging from 2.33–2.49 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of Ca–O bond distances ranging from 2.29–2.59 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two NbO6 octahedra, corners with five SiO4 tetrahedra, and edges with two equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Ca–O bond distances ranging from 2.31–2.48 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Ca–O bond distances ranging from 2.30–2.56 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five SiO4 tetrahedra, and edges with two equivalent CaO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Ca–O bond distances ranging from 2.35–2.48 Å. In the sixth Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.22–2.87 Å. In the seventh Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.21–2.77 Å. In the eighth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.86 Å. In the ninth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.87 Å. In the tenth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.84 Å. In the eleventh Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.87 Å. In the twelfth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.23–2.64 Å. In the thirteenth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.94 Å. There are three inequivalent Nb+4.67+ sites. In the first Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three CaO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the second Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one CaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Nb–O bond distances ranging from 1.89–2.30 Å. In the third Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two CaO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 59–64°. There are a spread of Nb–O bond distances ranging from 1.91–2.17 Å. There are eight 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 NbO6 octahedra, corners with four CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–66°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with four CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–78°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–65°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–67°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–61°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–72°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NbO6 octahedra, corners with three CaO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–67°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two CaO6 octahedra, corners with two NbO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–63°. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Si4+ atom. In the third O2- site, O2- is bonded to three Ca2+ and one Nb+4.67+ atom to form distorted OCa3Nb trigonal pyramids that share corners with three OCa3Si tetrahedra and an edgeedge with one OCa4 tetrahedra. In the fourth O2- site, O2- is bonded to three Ca2+ and one Nb+4.67+ atom to form distorted OCa3Nb tetrahedra that share corners with five OCa3Si tetrahedra and an edgeedge with one OCa2Nb2 tetrahedra. In the fifth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted OCa3Si tetrahedra that share corners with three OCa2Nb2 tetrahedra and a cornercorner with one OCa3Nb trigonal pyramid. In the sixth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted OCa3Si tetrahedra that share corners with two OCa2Nb2 tetrahedra and a cornercorner with one OCa3Nb trigonal pyramid. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the ninth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted corner-sharing OCa3Si tetrahedra. In the tenth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted OCa3Si tetrahedra that share corners with two OCa4 tetrahedra and a cornercorner with one OCa3Nb trigonal pyramid. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Nb+4.67+ atom. In the twelfth O2- site, O2- is bonded to two Ca2+ and two Nb+4.67+ atoms to form distorted OCa2Nb2 tetrahedra that share corners with four OCa3Nb tetrahedra and an edgeedge with one OCa2Nb2 tetrahedra. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the twenty-third O2- site, O2- is bonded to four Ca2+ atoms to form OCa4 tetrahedra that share corners with three OCa3Si tetrahedra and an edgeedge with one OCa3Nb trigonal pyramid. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Nb+4.67+ atom. In the twenty-fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Nb+4.67+ atom. In the twenty-sixth O2- site, O2- is bonded to two Ca2+ and two Nb+4.67+ atoms to form distorted OCa2Nb2 tetrahedra that share corners with two OCa3Si tetrahedra and edges with two OCa3Nb tetrahedra. In the twenty-seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Nb+4.67+, and one Si4+ atom. In the twenty-ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ca2+ and two Si4+ atoms. In the thirtieth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two Si4+ atoms. In the thirty-first O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the thirty-second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom. In the thirty-third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ca2+ and one Si4+ atom. In the thirty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the thirty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom. In the thirty-sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Si4+ atom.},
doi = {10.17188/1681582},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2020},
month = {4}
}