Materials Data on NaNpSeO6 by Materials Project
NaNpSeO6 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Na1+ is bonded to five O2- atoms to form distorted NaO5 square pyramids that share a cornercorner with one NpO7 pentagonal bipyramid, an edgeedge with one NpO7 pentagonal bipyramid, and edges with two equivalent NaO5 square pyramids. There are a spread of Na–O bond distances ranging from 2.28–2.53 Å. Np7+ is bonded to seven O2- atoms to form distorted NpO7 pentagonal bipyramids that share a cornercorner with one NaO5 square pyramid, edges with two equivalent NpO7 pentagonal bipyramids, and an edgeedge with one NaO5 square pyramid. There are a spread of Np–O bond distances ranging from 1.79–2.57 Å. Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.73 Å) and two longer (1.74 Å) Se–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Np7+ and one Se4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Np7+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Np7+, and one Se4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Na1+ and one Np7+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to two equivalent Na1+ atoms.