Materials Data on KNO3 by Materials Project

KNO3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.89–2.97 Å. N5+ is bonded in a trigonal planar geometry to three O2- atoms. All N–O bond lengths are 1.27 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent K1+ and one N5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent K1+ and one N5+ atom.