Li4NpO5 is Caswellsilverite-like structured and crystallizes in the tetragonal I4/m space group. Li(1) is bonded to one O(1) and five equivalent O(2) atoms to form LiO6 octahedra that share  a cornercorner with one Np(1)O6 octahedra, corners with five equivalent Li(1)O6 octahedra, edges with three equivalent Np(1)O6 octahedra, and edges with nine equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. Np(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NpO6 octahedra that share corners with two equivalent Np(1)O6 octahedra, corners with four equivalent Li(1)O6 octahedra, and edges with twelve equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Li(1) and two equivalent Np(1) atoms to form OLi4Np2 octahedra that share corners with two equivalent O(1)Li4Np2 octahedra, corners with four equivalent O(2)Li5Np octahedra, and edges with twelve equivalent O(2)Li5Np octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second O site, O(2) is bonded to five equivalent Li(1) and one Np(1) atom to form OLi5Np octahedra that share  a cornercorner with one O(1)Li4Np2 octahedra, corners with five equivalent O(2)Li5Np octahedra, edges with three equivalent O(1)Li4Np2 octahedra, and edges with nine equivalent O(2)Li5Np octahedra. The corner-sharing octahedral tilt angles range from 0-9°.
Li4NpO5 is Caswellsilverite-like structured and crystallizes in the tetragonal I4/m space group. Li(1) is bonded to one O(1) and five equivalent O(2) atoms to form LiO6 octahedra that share  a cornercorner with one Np(1)O6 octahedra, corners with five equivalent Li(1)O6 octahedra, edges with three equivalent Np(1)O6 octahedra, and edges with nine equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. The Li(1)-O(1) bond length is 2.15 Å. There are a spread of Li(1)-O(2) bond distances ranging from 2.02-2.26 Å. Np(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NpO6 octahedra that share corners with two equivalent Np(1)O6 octahedra, corners with four equivalent Li(1)O6 octahedra, and edges with twelve equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Both Np(1)-O(1) bond lengths are 2.20 Å. All Np(1)-O(2) bond lengths are 1.99 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Li(1) and two equivalent Np(1) atoms to form OLi4Np2 octahedra that share corners with two equivalent O(1)Li4Np2 octahedra, corners with four equivalent O(2)Li5Np octahedra, and edges with twelve equivalent O(2)Li5Np octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second O site, O(2) is bonded to five equivalent Li(1) and one Np(1) atom to form OLi5Np octahedra that share  a cornercorner with one O(1)Li4Np2 octahedra, corners with five equivalent O(2)Li5Np octahedra, edges with three equivalent O(1)Li4Np2 octahedra, and edges with nine equivalent O(2)Li5Np octahedra. The corner-sharing octahedral tilt angles range from 0-9°.