DOE OSTI2020
NaCd3 is Uranium Silicide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Na is bonded to twelve Cd atoms to form NaCd12 cuboctahedra that share corners with six equivalent NaCd12 cuboctahedra, corners with twelve equivalent CdNa4Cd8 cuboctahedra, edges with eighteen CdNa4Cd8 cuboctahedra, faces with eight equivalent NaCd12 cuboctahedra, and faces with twelve CdNa4Cd8 cuboctahedra. All Na–Cd bond lengths are 3.24 Å. There are two inequivalent Cd sites. In the first Cd site, Cd is bonded to four equivalent Na and eight Cd atoms to form distorted CdNa4Cd8 cuboctahedra that share corners with four equivalent NaCd12 cuboctahedra, corners with fourteen CdNa4Cd8 cuboctahedra, edges with six equivalent NaCd12 cuboctahedra, edges with twelve CdNa4Cd8 cuboctahedra, faces with four equivalent NaCd12 cuboctahedra, and faces with sixteen CdNa4Cd8 cuboctahedra. There are six shorter (3.22 Å) and two longer (3.26 Å) Cd–Cd bond lengths. In the second Cd site, Cd is bonded to four equivalent Na and eight equivalent Cd atoms to form distorted CdNa4Cd8 cuboctahedra that share corners with four equivalent NaCd12 cuboctahedra, corners with fourteen CdNa4Cd8 cuboctahedra, edges with six equivalent NaCd12 cuboctahedra, edges with twelve equivalent CdNa4Cd8 cuboctahedra, faces with four equivalent NaCd12 cuboctahedra, and faces with sixteen CdNa4Cd8 cuboctahedra.