A calorimetric and thermodynamic investigation of the synthetic analogs of cobaltomenite, CoSeO3·2H2O, and ahlfeldite, NiSeO3·2H2O

M.V. Charykova, V.G. Krivovichev, M.I. Lelet, O.S. Yakovenko, E.V. Suleimanov, W. Depmeier, V.V. Semenova, M.L. Zorina

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Thermophysical and thermochemical calorimetric investigations were carried out on synthetic analogs of two minerals: cobaltomenite (CoSeO 3·2H2O) and ahlfeldite (NiSeO3· 2H2O). The synthesis was realized by mixing of aqueous solutions of cobalt and nickel nitrates, accordingly, and sodium selenite, acidified with the help of a solution of nitric acid and characterized by X-ray powder diffraction and FTIR spectroscopy methods. The low-temperature heat capacities of CoSeO3·2H2O and NiSeO3·2H 2O were measured using adiabatic calorimetry between 8 and 340 K, and the third-law entropies were determined. Values of S° (298 K, CoSeO 3·2H2O, cr.) = 183.2 ± 1.0 J/(mol·K) and S° (298 K, NiSeO3·2H2O, cr.) = 172.9 ± 1.0 J/(mol·K) are obtained with an uncertainty of 0.5%. The enthalpies of formation for CoSeO3·2H2O and NiSeO3·2H2O were determined by solution calorimetry with H2SO4 solution as the solvent and giving ΔfH° (298 K, CoSeO3·2H2O, cr.) = -1135.3 kJ/mol, ΔfH° (298 K, NiSeO3· 2H2O, cr.) = -1133.3 kJ/mol. The Gibbs
Original languageEnglish
Pages (from-to)742-748
Number of pages7
JournalAmerican Mineralogist
Volume99
Issue number4
DOIs
StatePublished - 2014

Fingerprint

Dive into the research topics of 'A calorimetric and thermodynamic investigation of the synthetic analogs of cobaltomenite, CoSeO3·2H2O, and ahlfeldite, NiSeO3·2H2O'. Together they form a unique fingerprint.

Cite this