Materials Data on Np2Cr3(NO4)4 by Materials Project
Np2Cr3O16(N2)2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of eight ammonia molecules and one Np2Cr3O16 sheet oriented in the (0, 1, 1) direction. In the Np2Cr3O16 sheet, there are two inequivalent Np+6.50+ sites. In the first Np+6.50+ site, Np+6.50+ is bonded to seven O2- atoms to form distorted NpO7 pentagonal bipyramids that share corners with three CrO4 tetrahedra, an edgeedge with one NpO7 pentagonal bipyramid, and an edgeedge with one CrO4 tetrahedra. There are a spread of Np–O bond distances ranging from 1.77–2.45 Å. In the second Np+6.50+ site, Np+6.50+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Np–O bond distances ranging from 1.77–2.63 Å. There are three inequivalent Cr5+ sites. In the first Cr5+ site, Cr5+ is bonded to four O2- atoms to form CrO4 tetrahedra that share a cornercorner with one NpO7 pentagonal bipyramid and an edgeedge with one NpO7 pentagonal bipyramid. There are a spread of Cr–O bond distances ranging from 1.60–1.78 Å. In the second Cr5+ site, Cr5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Cr–O bond distances ranging from 1.60–1.76 Å. In the third Cr5+ site, Cr5+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with two equivalent NpO7 pentagonal bipyramids. There are a spread of Cr–O bond distances ranging from 1.59–1.74 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Np+6.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Np+6.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Np+6.50+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Np+6.50+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Np+6.50+ and one Cr5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two Np+6.50+ and one Cr5+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one Cr5+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one Cr5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Np+6.50+ and one Cr5+ atom. In the tenth O2- site, O2- is bonded in a linear geometry to one Np+6.50+ and one Cr5+ atom. In the eleventh O2- site, O2- is bonded in a single-bond geometry to one Cr5+ atom. In the twelfth O2- site, O2- is bonded in a single-bond geometry to one Cr5+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Np+6.50+ and one Cr5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Np+6.50+ and one Cr5+ atom. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Np+6.50+ and one Cr5+ atom. In the sixteenth O2- site, O2- is bonded in a single-bond geometry to one Cr5+ atom.