Materials Data on K2Ca(NO2)4 by Materials Project
K2Ca(NO2)4 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one K2Ca(NO2)4 sheet oriented in the (0, 0, 1) direction. K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.73–2.89 Å. Ca2+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent O2- atoms. All Ca–O bond lengths are 2.31 Å. There are two inequivalent N3+ sites. In the first N3+ site, N3+ is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both N–O bond lengths are 1.30 Å. In the second N3+ site, N3+ is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both N–O bond lengths are 1.28 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ca2+, and one N3+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+ and one N3+ atom.