K(NpSe3)2 crystallizes in the orthorhombic Immm space group. K(1) is bonded in a distorted body-centered cubic geometry to eight equivalent Se(2) atoms. Np(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Np(1), and two equivalent Se(2) atoms. In the second Se site, Se(1) is bonded to four equivalent Np(1) atoms to form a mixture of edge and corner-sharing SeNp4 trigonal pyramids.
K(NpSe3)2 crystallizes in the orthorhombic Immm space group. K(1) is bonded in a distorted body-centered cubic geometry to eight equivalent Se(2) atoms. All K(1)-Se(2) bond lengths are 3.41 Å. Np(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. There are two shorter (2.89 Å) and two longer (2.92 Å) Np(1)-Se(1) bond lengths. All Np(1)-Se(2) bond lengths are 2.95 Å. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Np(1), and two equivalent Se(2) atoms. There is one shorter (2.65 Å) and one longer (2.86 Å) Se(2)-Se(2) bond length. In the second Se site, Se(1) is bonded to four equivalent Np(1) atoms to form a mixture of edge and corner-sharing SeNp4 trigonal pyramids.