Materials Data on Na3NpO8 by Materials Project

Na3NpO8 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.40–2.83 Å. In the second Na site, Na is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Na–O bond distances ranging from 2.33–2.88 Å. Np is bonded in a distorted octahedral geometry to six O atoms. There are a spread of Np–O bond distances ranging from 1.90–2.44 Å. There are four inequivalent O sites. In the first O site, O is bonded in a distorted see-saw-like geometry to two Na, one Np, and one O atom. The O–O bond length is 1.35 Å. In the second O site, O is bonded to three Na and one Np atom to form a mixture of distorted edge and corner-sharing ONa3Np trigonal pyramids. In the third O site, O is bonded in a distorted rectangular see-saw-like geometry to three Na and one Np atom. In the fourth O site, O is bonded in a 4-coordinate geometry to three Na and one O atom.