Structural study of dehydration mechanisms of NH4Th(NO3)5·9H2O

Abstract The new pentanitrate thorium compounds NH 4 Th(NO 3 ) 5 ·nH 2 O were synthesized and their crystal structures were determined by X-ray diffraction analysis: space group P 2 1 / n , a = 10.5476(5), b = 14.0444(7), c = 15.5287(8) A, β = 109.4999(7)°, Z = 4; R = 0.0246 (NH 4 Th(NO 3 ) 5 ·9H 2 O); space group P 2 1 2 1 2 1 , a = 8.7039(4), b = 11.9985(6), c = 16.3531(8) A, Z = 4; R = 0.0259 (NH 4 Th(NO 3 ) 5 ·5H 2 O). Features of structural changes in the dehydration were revealed. Conditions of thermal decomposition of the thorium compound were established using differential scanning calorimetry. The compound was investigated by IR spectroscopy and its bands are assigned.