Materials Data on NaCa3 by Materials Project
NaCa3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Na is bonded to twelve Ca atoms to form NaCa12 cuboctahedra that share corners with four equivalent NaCa12 cuboctahedra, corners with eight equivalent CaNa4Ca8 cuboctahedra, edges with eight equivalent NaCa12 cuboctahedra, edges with sixteen equivalent CaNa4Ca8 cuboctahedra, faces with four equivalent NaCa12 cuboctahedra, and faces with fourteen CaNa4Ca8 cuboctahedra. There are four shorter (3.81 Å) and eight longer (3.92 Å) Na–Ca bond lengths. There are two inequivalent Ca sites. In the first Ca site, Ca is bonded to four equivalent Na and eight Ca atoms to form CaNa4Ca8 cuboctahedra that share corners with twelve equivalent CaNa4Ca8 cuboctahedra, edges with eight equivalent NaCa12 cuboctahedra, edges with sixteen CaNa4Ca8 cuboctahedra, faces with four equivalent NaCa12 cuboctahedra, and faces with fourteen CaNa4Ca8 cuboctahedra. There are four shorter (3.81 Å) and four longer (3.92 Å) Ca–Ca bond lengths. In the second Ca site, Ca is bonded to four equivalent Na and eight equivalent Ca atoms to form CaNa4Ca8 cuboctahedra that share corners with four equivalent CaNa4Ca8 cuboctahedra, corners with eight equivalent NaCa12 cuboctahedra, edges with twenty-four CaNa4Ca8 cuboctahedra, faces with six equivalent NaCa12 cuboctahedra, and faces with twelve CaNa4Ca8 cuboctahedra.