Oxygen versus nitrogen interactions in lithium dinitramidate dihydrate and pyridinium dinitramidate

The title compounds, diaquadinitramidatolithium(I), [Li( N3O4)(H2O)(2)], (I), and pyridinium dinitramidate, C5H6N+ center dot N3O4-, (II), differ significantly in their cation-anion contacts. The Li+ atom of (I) is coordinated by two O atoms of the dinitramide anion in a chelate and by four additional water molecules, with the Li and central N atom of the anion on a twofold rotation axis. The pyridinium cation of (II) exhibits a contact with the dinitramide anion via an intermolecular N-H center dot center dot center dot N hydrogen bridge. These interactions are compared with those found in reported anhydrous lithium dinitramide and ammonium dinitramide salts.