DOE OSTI2020
Ca7Ge is beta-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are twenty-five inequivalent Ca sites. In the first Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the second Ca site, Ca is bonded to twelve Ca atoms to form CaCa12 cuboctahedra that share corners with twelve equivalent CaCa12 cuboctahedra, edges with twenty-four CaCa10Ge2 cuboctahedra, faces with six equivalent GeCa12 cuboctahedra, and faces with twelve CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. In the third Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the fourth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the fifth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the sixth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the seventh Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the eighth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the ninth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the tenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the eleventh Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twelfth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the thirteenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the fourteenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the fifteenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the sixteenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the seventeenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the eighteenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the nineteenth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twentieth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twenty-first Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twenty-second Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. The Ca–Ca bond length is 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twenty-third Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twenty-fourth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa10Ge2 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. Both Ca–Ge bond lengths are 3.72 Å. In the twenty-fifth Ca site, Ca is bonded to ten Ca and two equivalent Ge atoms to form distorted CaCa10Ge2 cuboctahedra that share corners with twelve CaCa10Ge2 cuboctahedra, edges with four equivalent GeCa12 cuboctahedra, edges with twenty CaCa12 cuboctahedra, faces with two equivalent GeCa12 cuboctahedra, and faces with sixteen CaCa10Ge2 cuboctahedra. Both Ca–Ge bond lengths are 3.72 Å. Ge is bonded to twelve Ca atoms to form distorted GeCa12 cuboctahedra that share corners with twelve equivalent GeCa12 cuboctahedra, edges with twenty-four CaCa10Ge2 cuboctahedra, and faces with eighteen CaCa10Ge2 cuboctahedra.