Structural investigations on Sr(NO2)2•X2O (X=H, D): a vibrational analysis

Abstract The infrared absorption (at 300 K and 93 K) and the laser Raman spectra (at 300 K) of polycrystalline Sr(NO 2 ) 2 · H 2 O and its deuterated analogue in the range 30–4000 cm −1 have been studied. The salt is shown to contain two non-equivalent water molecules and at least three non-equivalent nitrite groups per unit cell. The average bond enthalpies for the two kinds of water molecules are estimated to be 16.5 and 11.6 kJ mol −1 . The spectra exhibit exceptionally low intensity of the bending fundamentals of H 2 O molecules. A cyclic structure formed by H 2 O(I) and H 2 O(II) is proposed to explain this behaviour.