DOE OSTI2020
Ca(MoO2)2 is Spinel-like 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 MoO6 octahedra. The corner-sharing octahedra tilt angles range from 54–64°. There are a spread of Ca–O bond distances ranging from 2.19–2.27 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.39 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MoO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.26–2.42 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.40 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.32–2.39 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 five MoO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.25–2.48 Å. There are twelve inequivalent Mo3+ sites. In the first Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.13–2.28 Å. In the second Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 43–66°. There are a spread of Mo–O bond distances ranging from 1.99–2.21 Å. In the third Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.08–2.28 Å. In the fourth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.13–2.28 Å. In the fifth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with six MoO4 tetrahedra, edges with two equivalent MoO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.16–2.26 Å. In the sixth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 44–77°. There are a spread of Mo–O bond distances ranging from 2.09–2.25 Å. In the seventh Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with six MoO4 tetrahedra, edges with two equivalent MoO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.15–2.24 Å. In the eighth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five MoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.10–2.36 Å. In the ninth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 44–71°. There are a spread of Mo–O bond distances ranging from 2.08–2.20 Å. In the tenth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five MoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.13–2.32 Å. In the eleventh Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 46–76°. There are a spread of Mo–O bond distances ranging from 2.07–2.26 Å. In the twelfth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 48–62°. There are a spread of Mo–O bond distances ranging from 1.98–2.04 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 Mo3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the fourth O2- site, O2- is bonded to one Ca2+ and three Mo3+ atoms to form distorted corner-sharing OCaMo3 trigonal pyramids. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the sixth O2- site, O2- is bonded to one Ca2+ and three Mo3+ atoms to form corner-sharing OCaMo3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a trigonal pyramidal geometry to one Ca2+ and three Mo3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Mo3+ atoms. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the twenty-third O2- site, O2- is bonded in a trigonal pyramidal geometry to one Ca2+ and three Mo3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms.