DOE OSTI2020
NpPd3 is Uranium Silicide-like structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Np sites. In the first Np site, Np is bonded to twelve Pd atoms to form NpPd12 cuboctahedra that share corners with six equivalent NpPd12 cuboctahedra, edges with twelve PdNp4Pd8 cuboctahedra, faces with six PdNp4Pd8 cuboctahedra, and faces with eight NpPd12 cuboctahedra. There are a spread of Np–Pd bond distances ranging from 2.92–2.99 Å. In the second Np site, Np is bonded to twelve Pd atoms to form NpPd12 cuboctahedra that share corners with twelve equivalent NpPd12 cuboctahedra, edges with twelve PdNp4Pd8 cuboctahedra, faces with six equivalent NpPd12 cuboctahedra, and faces with six PdNp4Pd8 cuboctahedra. There are a spread of Np–Pd bond distances ranging from 2.92–2.95 Å. There are four inequivalent Pd sites. In the first Pd site, Pd is bonded in a distorted square co-planar geometry to four Np and four Pd atoms. All Pd–Pd bond lengths are 2.93 Å. In the second Pd site, Pd is bonded in a distorted square co-planar geometry to four Np and four equivalent Pd atoms. All Pd–Pd bond lengths are 2.93 Å. In the third Pd site, Pd is bonded to four Np and eight Pd atoms to form distorted PdNp4Pd8 cuboctahedra that share corners with twelve equivalent PdNp4Pd8 cuboctahedra, edges with eight NpPd12 cuboctahedra, edges with eight equivalent PdNp4Pd8 cuboctahedra, faces with four NpPd12 cuboctahedra, and faces with four equivalent PdNp4Pd8 cuboctahedra. There are two shorter (2.83 Å) and two longer (3.03 Å) Pd–Pd bond lengths. In the fourth Pd site, Pd is bonded to four Np and eight Pd atoms to form distorted PdNp4Pd8 cuboctahedra that share corners with twelve equivalent PdNp4Pd8 cuboctahedra, edges with eight NpPd12 cuboctahedra, edges with eight PdNp4Pd8 cuboctahedra, faces with four NpPd12 cuboctahedra, and faces with four PdNp4Pd8 cuboctahedra. There are one shorter (2.83 Å) and one longer (3.01 Å) Pd–Pd bond lengths.