DOE OSTI2020
CrC2N3H4CNH3N2H2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of two hydrogen molecules; two methylamine molecules; two nitrogen molecules; and one CrC2N3H4 ribbon oriented in the (1, 0, 0) direction. In the CrC2N3H4 ribbon, there are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded in a distorted hexagonal bipyramidal geometry to two equivalent C2+, four N3-, and two equivalent H1+ atoms. Both Cr–C bond lengths are 2.01 Å. There are two shorter (2.16 Å) and two longer (2.18 Å) Cr–N bond lengths. Both Cr–H bond lengths are 1.81 Å. In the second Cr3+ site, Cr3+ is bonded in a distorted square co-planar geometry to two equivalent N3- and two equivalent H1+ atoms. Both Cr–N bond lengths are 1.87 Å. Both Cr–H bond lengths are 1.84 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Cr3+ and one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a tetrahedral geometry to one N3- and three H1+ atoms. The C–N bond length is 1.41 Å. All C–H bond lengths are 1.10 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted T-shaped geometry to two Cr3+ and one N3- atom. The N–N bond length is 1.19 Å. In the second N3- site, N3- is bonded in a 2-coordinate geometry to one Cr3+ and one N3- atom. In the third N3- site, N3- is bonded in a linear geometry to two C2+ atoms. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a water-like geometry to two Cr3+ atoms. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom.