DOE OSTI2020
Ba(CN2)2(CN)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional and consists of four CN clusters and one Ba(CN2)2 framework. In each CN cluster, there are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.18 Å) and one longer (1.28 Å) C–N bond length. In the second C4+ site, C4+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.22 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to two C4+ atoms. In the second N3- site, N3- is bonded in a single-bond geometry to one C4+ atom. In the Ba(CN2)2 framework, Ba2+ is bonded in a distorted pentagonal planar geometry to five N3- atoms. There are a spread of Ba–N bond distances ranging from 2.78–2.89 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a bent 150 degrees geometry to two N3- atoms. There is one shorter (1.23 Å) and one longer (1.37 Å) C–N bond length. In the second C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.20 Å) and one longer (1.28 Å) C–N bond length. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted water-like geometry to one Ba2+ and two C4+ atoms. In the second N3- site, N3- is bonded in a distorted single-bond geometry to one C4+ and one N3- atom. The N–N bond length is 1.23 Å. In the third N3- site, N3- is bonded in a distorted trigonal planar geometry to two equivalent Ba2+ and one N3- atom. In the fourth N3- site, N3- is bonded in a 1-coordinate geometry to two equivalent Ba2+ and one C4+ atom.