A carbon-free inorganic-metal complex consisting of an all-nitrogen pentazole anion, a Zn(II) cation and H2O

A carbon-free inorganic-metal complex [Zn(H2O)(4)(N-5)(2)]center dot 4H(2)O was synthesized by the ion metathesis of [Na(H2O)(N5)]center dot 2H(2)O solution with Zn(NO3)(2)center dot 6H(2)O. The complex was well characterized by IR and Raman spectroscopy, elemental analysis (EA), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). The structure of the complex was confirmed by single-crystal X-ray crystallography and a Zn(II) ion is coordinated in a quadrilateral bipyramid environment in which the axial position is formed by two nitrogen atoms (N1) from two pentazolate rings (cyclo-N-5(-)) and the equatorial plane is formed by four oxygen atoms (O1) from four coordinated water molecules. The thermal analysis of [Zn(H2O)(4)(N-5)(2)]center dot 4H(2)O reveals that although water plays an important role in stabilizing cyclo-N-5(-), dehydration does not cause immediate decomposition of the anion. However, cyclo-N-5(-) decomposed into N-3(-) and N-2 gas at 107.9 degrees C (onset). Based on its chemical compatibility and stability, the complex exhibits promising potential as a modern environmentally-friendly energetic material.