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Materials Data on SiO2 by Materials Project

SiO2 is High (Orthorhombic) Tridymite-like structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. there are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.61 Å) and three longer (1.62 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. All Si–O bond lengths are 1.62 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.61 Å) and two longer (1.62 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.61 Å) and two longer (1.62 Å) Si–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. 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 linear geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.64 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. 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 bent 150 degrees geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Low Tridymite-like structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.63 Å) Si–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Cuprite structured and crystallizes in the cubic Pn-3m space group. The structure is three-dimensional. Si4+ is bonded to four equivalent O2- atoms to form corner-sharing SiO4 tetrahedra. All Si–O bond lengths are 1.65 Å. O2- is bonded in a linear geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Anatase-like structured and crystallizes in the cubic Ia-3 space group. The structure is three-dimensional. there are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. 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 distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is High (Orthorhombic) Tridymite-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. All Si–O bond lengths are 1.62 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 crystallizes in the orthorhombic C222 space group. The structure is three-dimensional. there are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.63 Å) and two longer (1.65 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.66 Å) Si–O bond length. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.66 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.66 Å) Si–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is quartz (beta)-like structured and crystallizes in the cubic I-43m space group. The structure is three-dimensional. Si4+ is bonded to four equivalent O2- atoms to form corner-sharing SiO4 tetrahedra. All Si–O bond lengths are 1.62 Å. O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.

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Materials Data on Ca(SiO2)8 by Materials Project

Ca(SiO2)8 is Low Tridymite-derived structured and crystallizes in the monoclinic Pc space group. The structure is three-dimensional. Ca is bonded in a 4-coordinate geometry to four O atoms. There are a spread of Ca–O bond distances ranging from 2.56–2.70 Å. There are eight inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. In the second Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. In the third Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fourth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the fifth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the sixth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the seventh Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. In the eighth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are sixteen inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Ca and two Si atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the seventh O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and two Si atoms. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and two Si atoms. In the tenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and two Si atoms. In the twelfth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirteenth O site, O is bonded in a linear geometry to two Si atoms. In the fourteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fifteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the sixteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms.

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Materials Data on SiO2 by Materials Project

SiO2 is quartz (alpha)-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eighteen inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is three shorter (1.65 Å) and one longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the ninth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the tenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the eleventh Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is one shorter (1.65 Å) and three longer (1.66 Å) Si–O bond length. In the twelfth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the thirteenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the fourteenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the fifteenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the sixteenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. In the seventeenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. In the eighteenth Si4+ site, Si4+ is bonded to four O2- atoms to form distorted corner-sharing SiO4 tetrahedra. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the seventeenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the nineteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twentieth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twenty-ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirtieth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirty-second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirty-third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirty-fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirty-sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms.

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Materials Data on SiO2 by Materials Project

SiO2 is quartz (alpha)-like structured and crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.64 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.61 Å) and two longer (1.63 Å) Si–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. 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 bent 150 degrees geometry to two 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 linear geometry to two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.

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Materials Data on SiO2 by Materials Project

SiO2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of four trioxidane molecules and two Si14O25 sheets oriented in the (1, 0, 0) direction. In each Si14O25 sheet, there are seven inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded in a water-like geometry to two O2- atoms. There is one shorter (1.64 Å) and one longer (1.65 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Si–O bond distances ranging from 1.66–2.09 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.62 Å) and two longer (1.65 Å) Si–O bond length. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form a mixture of corner and edge-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in an L-shaped geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in an L-shaped geometry to two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Si4+ and one O2- atom. The O–O bond length is 1.52 Å. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms. In the eleventh O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on K(SiO2)2 by Materials Project

K(SiO2)2 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. K is bonded in a trigonal planar geometry to three equivalent O atoms. All K–O bond lengths are 3.18 Å. Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.66 Å) and one longer (1.67 Å) Si–O bond length. There are two inequivalent O sites. In the first O site, O is bonded in a linear geometry to two equivalent Si atoms. In the second O site, O is bonded in a linear geometry to three equivalent K and two equivalent Si atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are eight inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on SiO2 by Materials Project

SiO2 is Low Tridymite-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.63 Å) Si–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on Na(SiO2)3 by Materials Project

Na(SiO2)3 crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Na is bonded in a distorted hexagonal planar geometry to three equivalent O atoms. All Na–O bond lengths are 2.24 Å. Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. There are three inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two equivalent Si atoms. In the second O site, O is bonded in a linear geometry to two equivalent Si atoms. In the third O site, O is bonded in a distorted trigonal planar geometry to one Na and two equivalent Si atoms.

36 MATERIALS SCIENCE↗

Enhanced Interfacial Stability of Si Anodes for Li-Ion Batteries via Surface SiO2 Coating

Silicon is a promising alloying anode for lithium-ion batteries owing to its high capacity and low cost. However, its use has been hampered by mechanical failure arising from the large volume change upon cycling and by an insufficiently stable solid-electrolyte interphase (SEI). SEI formation depends on the Si surface, which is often an oxide (SiO x ). In this study we compare three different Si surfaces using Si wafers: 1.3 nm native SiO x , 1.4 nm thermally grown SiO2, and a SiOx-free surface. The oxide-free surface showed the worst electrochemical performance, never exceeding 94% Coulombic efficiency (CE). Furthermore, it also exhibited the thickest SEI and the highest overpotential for lithiation, which correlated with uninhibited electrolyte reduction and the incorporation of P-F species into the SEI. The oxide-coated surfaces performed significantly better, demonstrating a CE above 99% beyond the second cycle, low overpotential for lithiation, and a thinner and more stable SEI. The oxides lower the onset potential for electrolyte reduction, and yield an SEI with fewer P-F species. However, it was found that the CE with the native oxide surface decays from the fifth cycle onwards and correlates with a resurgence of electrolyte reduction. A 1-2 nm thermal SiO 2 coating is optimum for achieving a stable SEI that minimizes side reactions and sustains efficient cycling.

25 ENERGY STORAGE↗