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DOE OSTI2020

Materials Data on CaWO4 by Materials Project

CaWO4 is Zircon-like structured and crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight equivalent O2- atoms. There are four shorter (2.47 Å) and four longer (2.51 Å) Ca–O bond lengths. W6+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All W–O bond lengths are 1.83 Å. O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca3WO6 by Materials Project

Ca3WO6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent WO6 octahedra. The corner-sharing octahedra tilt angles range from 33–40°. There are a spread of Ca–O bond distances ranging from 2.29–2.36 Å. In the second 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 2.33–2.78 Å. W6+ is bonded to six O2- atoms to form WO6 octahedra that share corners with six equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 33–40°. There is two shorter (1.95 Å) and four longer (1.97 Å) W–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three Ca2+ and one W6+ atom to form distorted corner-sharing OCa3W tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one W6+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Ca2+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca3WO6 by Materials Project

Ca3WO6 is Ilmenite-like structured and crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share corners with two WO6 octahedra, corners with four equivalent CaO6 pentagonal pyramids, edges with two WO6 octahedra, and edges with four equivalent CaO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 30–39°. There are a spread of Ca–O bond distances ranging from 2.31–2.48 Å. There are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to six equivalent O2- atoms to form WO6 octahedra that share corners with six equivalent CaO6 pentagonal pyramids and edges with six equivalent CaO6 pentagonal pyramids. All W–O bond lengths are 1.97 Å. In the second W6+ site, W6+ is bonded to six equivalent O2- atoms to form WO6 octahedra that share corners with six equivalent CaO6 pentagonal pyramids and edges with six equivalent CaO6 pentagonal pyramids. All W–O bond lengths are 1.96 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ca2+ and one W6+ atom to form a mixture of distorted corner and edge-sharing OCa3W trigonal pyramids. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to three equivalent Ca2+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaW4O9 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2W3O8 by Materials Project

Ca2W3O8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share corners with seven WO6 octahedra, edges with three WO6 octahedra, and edges with two equivalent CaO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 6–53°. There are a spread of Ca–O bond distances ranging from 2.25–2.48 Å. There are two inequivalent W4+ sites. In the first W4+ site, W4+ is bonded to six O2- atoms to form WO6 octahedra that share corners with six equivalent CaO6 pentagonal pyramids, edges with four equivalent WO6 octahedra, and edges with two equivalent CaO6 pentagonal pyramids. There are four shorter (2.09 Å) and two longer (2.21 Å) W–O bond lengths. In the second W4+ site, W4+ is bonded to six O2- atoms to form WO6 octahedra that share corners with four equivalent CaO6 pentagonal pyramids, edges with four WO6 octahedra, and edges with two equivalent CaO6 pentagonal pyramids. There are four shorter (2.04 Å) and two longer (2.14 Å) W–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to one Ca2+ and two equivalent W4+ atoms. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to one Ca2+ and three W4+ atoms. In the third O2- site, O2- is bonded to two equivalent Ca2+ and two W4+ atoms to form a mixture of distorted edge and corner-sharing OCa2W2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaWO2 by Materials Project

CaWO2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to seven O2- atoms to form a mixture of distorted edge, corner, and face-sharing CaO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.32–2.57 Å. In the second Ca2+ site, Ca2+ is bonded to seven O2- atoms to form a mixture of distorted edge, corner, and face-sharing CaO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.29–2.61 Å. In the third Ca2+ site, Ca2+ is bonded to seven O2- atoms to form a mixture of distorted edge, corner, and face-sharing CaO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.33–2.57 Å. In the fourth Ca2+ site, Ca2+ is bonded to seven O2- atoms to form a mixture of distorted edge, corner, and face-sharing CaO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.36–2.60 Å. There are four inequivalent W2+ sites. In the first W2+ site, W2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 2.11–2.25 Å. In the second W2+ site, W2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 2.09–2.42 Å. In the third W2+ site, W2+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 2.08–2.58 Å. In the fourth W2+ site, W2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 2.11–2.35 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to three Ca2+ and three W2+ atoms to form distorted OCa3W3 octahedra that share corners with four OCa3W3 octahedra, corners with six OCa4W square pyramids, edges with four OCa3W3 octahedra, edges with three OCa4W square pyramids, and a faceface with one OCa4W square pyramid. The corner-sharing octahedra tilt angles range from 33–53°. In the second O2- site, O2- is bonded to three Ca2+ and three W2+ atoms to form distorted OCa3W3 octahedra that share corners with four OCa3W3 octahedra, corners with six OCa4W square pyramids, edges with four OCa3W3 octahedra, edges with three OCa4W square pyramids, and a faceface with one OCa4W square pyramid. The corner-sharing octahedra tilt angles range from 33–53°. In the third O2- site, O2- is bonded to three Ca2+ and three W2+ atoms to form OCa3W3 octahedra that share corners with four OCa3W3 octahedra, corners with six OCa4W square pyramids, edges with four OCa3W3 octahedra, edges with three OCa4W square pyramids, and a faceface with one OCa4W square pyramid. The corner-sharing octahedra tilt angles range from 40–51°. In the fourth O2- site, O2- is bonded to three Ca2+ and three W2+ atoms to form OCa3W3 octahedra that share corners with four OCa3W3 octahedra, corners with six OCa4W square pyramids, edges with four OCa3W3 octahedra, edges with three OCa4W square pyramids, and a faceface with one OCa4W square pyramid. The corner-sharing octahedra tilt angles range from 40–51°. In the fifth O2- site, O2- is bonded to four Ca2+ and one W2+ atom to form distorted OCa4W square pyramids that share corners with six OCa3W3 octahedra, corners with four OCa4W square pyramids, edges with three OCa3W3 octahedra, edges with four OCa4W square pyramids, and a faceface with one OCa3W3 octahedra. The corner-sharing octahedra tilt angles range from 25–63°. In the sixth O2- site, O2- is bonded to four Ca2+ and one W2+ atom to form distorted OCa4W square pyramids that share corners with six OCa3W3 octahedra, corners with four OCa4W square pyramids, edges with three OCa3W3 octahedra, edges with four OCa4W square pyramids, and a faceface with one OCa3W3 octahedra. The corner-sharing octahedra tilt angles range from 23–65°. In the seventh O2- site, O2- is bonded to four Ca2+ and one W2+ atom to form distorted OCa4W square pyramids that share corners with six OCa3W3 octahedra, corners with four OCa4W square pyramids, edges with three OCa3W3 octahedra, edges with four OCa4W square pyramids, and a faceface with one OCa3W3 octahedra. The corner-sharing octahedra tilt angles range from 26–65°. In the eighth O2- site, O2- is bonded to four Ca2+ and one W2+ atom to form distorted OCa4W square pyramids that share corners with six OCa3W3 octahedra, corners with four OCa4W square pyramids, edges with three OCa3W3 octahedra, edges with four OCa4W square pyramids, and a faceface with one OCa3W3 octahedra. The corner-sharing octahedra tilt angles range from 22–66°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaW5O7 by Materials Project

CaW5O7 crystallizes in the orthorhombic Cmcm 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 2.34–2.62 Å. There are three inequivalent W+2.40+ sites. In the first W+2.40+ site, W+2.40+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 29–42°. There are a spread of W–O bond distances ranging from 2.12–2.25 Å. In the second W+2.40+ site, W+2.40+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 29–51°. There are a spread of W–O bond distances ranging from 2.13–2.40 Å. In the third W+2.40+ site, W+2.40+ is bonded in a 2-coordinate geometry to six O2- atoms. There are two shorter (2.73 Å) and four longer (2.83 Å) W–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Ca2+ and five W+2.40+ atoms. In the second O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent W+2.40+ atoms to form distorted OCa2W2 tetrahedra that share corners with eight equivalent OCa2W3 square pyramids, corners with four OW6 tetrahedra, and edges with two equivalent OCa2W3 square pyramids. In the third O2- site, O2- is bonded to six W+2.40+ atoms to form distorted OW6 tetrahedra that share a cornercorner with one OCa2W3 square pyramid, corners with three OW6 tetrahedra, edges with two equivalent OCa2W3 square pyramids, and edges with five equivalent OW6 tetrahedra. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and three W+2.40+ atoms to form distorted OCa2W3 square pyramids that share corners with two equivalent OCa2W3 square pyramids, corners with five OW6 tetrahedra, edges with three equivalent OCa2W3 square pyramids, and edges with three OW6 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2W2O5 by Materials Project

Ca2W2O5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.40–3.05 Å. In the second Ca2+ site, Ca2+ is bonded in a 10-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.41–2.79 Å. There are two inequivalent W3+ sites. In the first W3+ site, W3+ is bonded to five O2- atoms to form distorted corner-sharing WO5 square pyramids. There are a spread of W–O bond distances ranging from 2.01–2.39 Å. In the second W3+ site, W3+ is bonded to five O2- atoms to form distorted corner-sharing WO5 square pyramids. There are a spread of W–O bond distances ranging from 1.99–2.41 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent W3+ atoms to form edge-sharing OCa4W2 octahedra. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+ and two W3+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+ and two W3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and two equivalent W3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two equivalent W3+ atoms. In the sixth O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent W3+ atoms to form edge-sharing OCa4W2 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaWO2 by Materials Project

CaWO2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are two shorter (2.31 Å) and three longer (2.32 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.33 Å. In the third Ca2+ site, Ca2+ is bonded to five O2- atoms to form a mixture of distorted corner and edge-sharing CaO5 square pyramids. There are a spread of Ca–O bond distances ranging from 2.21–2.54 Å. In the fourth Ca2+ site, Ca2+ is bonded to five O2- atoms to form a mixture of distorted corner and edge-sharing CaO5 square pyramids. There are a spread of Ca–O bond distances ranging from 2.22–2.53 Å. There are four inequivalent W2+ sites. In the first W2+ site, W2+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of W–O bond distances ranging from 2.18–2.28 Å. In the second W2+ site, W2+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of W–O bond distances ranging from 2.09–2.31 Å. In the third W2+ site, W2+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of W–O bond distances ranging from 2.08–2.32 Å. In the fourth W2+ site, W2+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of W–O bond distances ranging from 2.17–2.29 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W2+ atoms. In the second O2- site, O2- is bonded to three Ca2+ and three W2+ atoms to form OCa3W3 octahedra that share corners with four OCa3W2 trigonal bipyramids, edges with four OCa3W3 octahedra, and a faceface with one OCa3W2 trigonal bipyramid. In the third O2- site, O2- is bonded to three Ca2+ and three W2+ atoms to form OCa3W3 octahedra that share corners with four OCa3W2 trigonal bipyramids, edges with four OCa3W3 octahedra, and a faceface with one OCa3W2 trigonal bipyramid. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W2+ atoms. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two equivalent W2+ atoms. In the sixth O2- site, O2- is bonded to three Ca2+ and two equivalent W2+ atoms to form distorted OCa3W2 trigonal bipyramids that share corners with four OCa3W3 octahedra, edges with two equivalent OCa3W2 trigonal bipyramids, and a faceface with one OCa3W3 octahedra. The corner-sharing octahedra tilt angles range from 45–55°. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two equivalent W2+ atoms. In the eighth O2- site, O2- is bonded to three Ca2+ and two equivalent W2+ atoms to form distorted OCa3W2 trigonal bipyramids that share corners with four OCa3W3 octahedra, edges with two equivalent OCa3W2 trigonal bipyramids, and a faceface with one OCa3W3 octahedra. The corner-sharing octahedra tilt angles range from 44–55°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaWO3 by Materials Project

CaWO3 is Pb (Zr_0.50 Ti_0.48) O_3 structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.89 Å. W4+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of W–O bond distances ranging from 2.02–2.08 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ca2+ and two equivalent W4+ atoms to form distorted corner-sharing OCa3W2 trigonal bipyramids. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Ca2+ and two equivalent W4+ atoms. In the third O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Ca2+ and two equivalent W4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(WO2)2 by Materials Project

Ca(WO2)2 is beta indium sulfide-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 54–67°. There are three shorter (2.28 Å) and one longer (2.35 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three equivalent WO4 trigonal pyramids, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.42 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one WO4 tetrahedra, corners with two equivalent CaO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, an edgeedge with one CaO6 octahedra, and edges with five WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.42 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three equivalent WO4 trigonal pyramids, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.41 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two WO4 trigonal pyramids, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.22–2.49 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with two equivalent WO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, an edgeedge with one CaO6 octahedra, and edges with five WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.41 Å. There are twelve inequivalent W3+ sites. In the first W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share a cornercorner with one WO4 tetrahedra, corners with two equivalent CaO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, edges with three CaO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.14–2.21 Å. In the second W3+ site, W3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of W–O bond distances ranging from 1.97–2.07 Å. In the third W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent WO4 tetrahedra, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of W–O bond distances ranging from 2.06–2.27 Å. In the fourth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share a cornercorner with one WO4 tetrahedra, corners with two equivalent CaO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, edges with three CaO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.18–2.24 Å. In the fifth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with two WO4 trigonal pyramids, edges with two equivalent WO6 octahedra, and edges with four CaO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.24 Å. In the sixth W3+ site, W3+ is bonded to four O2- atoms to form WO4 trigonal pyramids that share corners with six CaO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 39–70°. There are a spread of W–O bond distances ranging from 1.97–2.36 Å. In the seventh W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with two WO4 trigonal pyramids, edges with two equivalent WO6 octahedra, and edges with four CaO6 octahedra. There are a spread of W–O bond distances ranging from 2.00–2.23 Å. In the eighth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with two equivalent WO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, edges with three CaO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.14–2.22 Å. In the ninth W3+ site, W3+ is bonded to four O2- atoms to form WO4 trigonal pyramids that share corners with six CaO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 43–79°. There are a spread of W–O bond distances ranging from 2.07–2.35 Å. In the tenth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with two equivalent WO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, edges with three CaO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.26 Å. In the eleventh W3+ site, W3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of W–O bond distances ranging from 1.97–2.04 Å. In the twelfth W3+ site, W3+ is bonded to four O2- atoms to form distorted WO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 51–75°. There are a spread of W–O bond distances ranging from 2.04–2.53 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the third O2- site, O2- is bonded to two Ca2+ and two W3+ atoms to form distorted OCa2W2 tetrahedra that share corners with two OCa2W2 tetrahedra, corners with four OCaW3 trigonal pyramids, and an edgeedge with one OCaW3 tetrahedra. In the fourth O2- site, O2- is bonded to one Ca2+ and three W3+ atoms to form distorted OCaW3 tetrahedra that share corners with two OCa2W2 tetrahedra, corners with four OCaW3 trigonal pyramids, and an edgeedge with one OCa2W2 tetrahedra. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the ninth O2- site, O2- is bonded in a trigonal non-coplanar geometry to two Ca2+ and one W3+ atom. In the tenth O2- site, O2- is bonded to one Ca2+ and three W3+ atoms to form OCaW3 trigonal pyramids that share corners with four OCa2W2 tetrahedra and corners with two OCaW3 trigonal pyramids. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one W3+ atom. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the seventeenth O2- site, O2- is bonded to two Ca2+ and two W3+ atoms to form distorted OCa2W2 tetrahedra that share corners with two OCa2W2 tetrahedra and corners with four OCaW3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded in a trigonal pyramidal geometry to one Ca2+ and three W3+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four W3+ atoms. In the twenty-second O2- site, O2- is bonded to one Ca2+ and three W3+ atoms to form distorted OCaW3 trigonal pyramids that share corners with four OCa2W2 tetrahedra, corners with two OCaW3 trigonal pyramids, and an edgeedge with one OCaW3 trigonal pyramid. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twenty-fourth O2- site, O2- is bonded to one Ca2+ and three W3+ atoms to form distorted OCaW3 trigonal pyramids that share corners with four OCa2W2 tetrahedra, corners with two OCaW3 trigonal pyramids, and an edgeedge with one OCaW3 trigonal pyramid.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(WO2)2 by Materials Project

Ca(WO2)2 is beta indium sulfide-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three equivalent CaO6 octahedra and corners with nine equivalent WO6 octahedra. The corner-sharing octahedra tilt angles range from 56–65°. There are three shorter (2.27 Å) and one longer (2.32 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three equivalent CaO4 tetrahedra and edges with six equivalent WO6 octahedra. There are three shorter (2.34 Å) and three longer (2.39 Å) Ca–O bond lengths. There are two inequivalent W3+ sites. In the first W3+ site, W3+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All W–O bond lengths are 2.02 Å. In the second W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent CaO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four equivalent WO6 octahedra. There are a spread of W–O bond distances ranging from 2.16–2.27 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent W3+ atoms. In the third O2- site, O2- is bonded to one Ca2+ and three equivalent W3+ atoms to form a mixture of distorted edge and corner-sharing OCaW3 tetrahedra. In the fourth O2- site, O2- is bonded to two Ca2+ and two equivalent W3+ atoms to form distorted OCa2W2 trigonal pyramids that share a cornercorner with one OCaW3 tetrahedra, corners with two equivalent OCa2W2 trigonal pyramids, an edgeedge with one OCaW3 tetrahedra, and edges with two equivalent OCa2W2 trigonal pyramids.

36 MATERIALS SCIENCE↗