Evidence of quasi-intramolecular redox reactions during thermal decomposition of ammonium hydroxodisulfitoferriate(III), (NH₄)₂[Fe(OH) (SO₃)₂]•H₂O

Author(s)

Tünde Kocsis, József Magyari, István E. Sajó, Tibor Pasinszki, Zlotán Homonnay, Imre M. Szilágyi, Attila Farkas, Zoltán May, Herta Silvia Effenberger, Sándor Szakáll, Rajendra P. Pawar, László Kótai

Abstract

Synthesis of ammonium hydroxodisulfitoferriate(III) , (diammonium catena- {bis(µ2- sulfito- O, O) - µ2- hydroxo- 2O} ferrate(III) monohydrate) (NH4) 2[Fe(OH) (SO3) 2] ·H2O (compd. 1) and its thermal behavior is reported. The compd. is stable in air. Its thermal decompn. proceeds without the expected quasi- intramol. oxidn. of sulfite ion with ferric ions. The disproportionation reaction of the ammonium sulfite, formed from the evolved NH3, SO2 and H2O in the main decompn. stage of 1, results in the formation of ammonium sulfate and ammonium sulfide. The ammonium sulfide is unstable at the decompn. temp. of 1 (150 °C) and transforms into NH3 and H2S which immediately forms elementary sulfur by reaction with SO2. The formation and decompn. of other intermediate compds. like (NH4) 2SnOx (n = 2, x = 3 and n = 3, x = 6) results in the same decompn. products (S, SO2 and NH3) . Two basic iron sulfates, formed in different ratios during synthesizing expts. performed under N2 or in the presence of air, have been detected as solid intermediates which contain ammonium ions. The final decompn. product was proved to be a- Fe2O3 (mineral name hematite).

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

Hungarian Academy of Sciences, University of Novi Sad (UNS), University of Pécs, Eötvös Loránd University Budapest, Budapest University of Technology and Economics, University of Miskolc, Deogiri College

Journal

Journal of Thermal Analysis and Calorimetry: an international forum for thermal studies

Volume

132

Pages

493-502

No. of pages

10

ISSN

1388-6150

DOI

https://doi.org/10.1007/s10973-017-6901-4

Publication date

04-2018

Peer reviewed

Yes

Austrian Fields of Science 2012

104003 Inorganic chemistry, 104026 Spectroscopy, 104017 Physical chemistry, 105113 Crystallography

Keywords

ASJC Scopus subject areas

Condensed Matter Physics, Physical and Theoretical Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/f83f5eea-89cb-4f95-9ebc-3831d2f1af5b