Thermal decomposition mechanism of iron(III) nitrate and characterization of intermediate products by the technique of computerized modeling

• Published in: Journal of thermal analysis and calorimetry Vol. 115; no. 1; pp. 145 - 151
• Main Authors: Melnikov, P., Nascimento, V. A., Arkhangelsky, I. V., Zanoni Consolo, L. Z., de Oliveira, L. C. S.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-01-2014; Springer
• Subjects: Analytical Chemistry; Calorimetry; Chemical properties; Chemistry; Chemistry and Materials Science; Condensing; Inorganic Chemistry; Iron; Measurement Science and Instrumentation; Methods; Monomers; Nitrates; Nitric acid; Phase transformations; Physical Chemistry; Polymer Sciences; Pyrolysis; Thermal decomposition; Toy industry; Oxynitrates; Thermal decomposition; Iron nitrate; Computer modeling
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-013-3339-1

The nonahydrate of iron(III) nitrate shows no phase transitions in the range of −40 to 0 °C. Both hexahydrate Fe(NO
3
)
3
·6H
2
O and nonahydrate Fe(NO
3
)
3
·9H
2
O have practically the same thermal behavior. Thermal decomposition of iron nitrate is a complex process which has a different mechanism than those described for other trivalent elements. Thermolysis begins with the successive condensation of 4 mol of the initial monomer accompanied by the loss of 4 mol of nitric acid. At higher temperature, hydrolytic processes continue with the gradual elimination of nitric acid from resulting tetramer and dimeric iron oxyhydroxide Fe
4
O
4
(OH)
4
is formed. After complete dehydration, oxyhydroxide is destroyed leaving behind 2 mol of Fe
2
O
3
. The molecular mechanics method provides a helpful insight into the structural arrangement of intermediate compounds.