Research output: Contribution to journal › Article › peer-review
Thermal behavior of ferric selenite hydrates (Fe 2(SeO 3) 3·3H 2O, Fe 2(SeO 3) 3·5H 2O) and the water content in the natural ferric selenite mandarinoite. / Holzheid , Astrid; Charykova, Marina V.; Krivovichev, Vladimir G.; Ledwig , Brenan; Fokina, Elena L.; Poroshina, Ksenia L.; Platonova, Natalia V.; Gurzhiy, Vladislav V.
In: Chemie der Erde, Vol. 78, No. 2, 01.05.2018, p. 228-240.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Thermal behavior of ferric selenite hydrates (Fe 2(SeO 3) 3·3H 2O, Fe 2(SeO 3) 3·5H 2O) and the water content in the natural ferric selenite mandarinoite
AU - Holzheid , Astrid
AU - Charykova, Marina V.
AU - Krivovichev, Vladimir G.
AU - Ledwig , Brenan
AU - Fokina, Elena L.
AU - Poroshina, Ksenia L.
AU - Platonova, Natalia V.
AU - Gurzhiy, Vladislav V.
N1 - Holzheid A., Charykova M.V., Krivovichev V.G., Ledwig B., Fokina E.L., Poroshina K.L., Platonova N.V., Gurzhiy V.V. Thermal behavior of ferric selenite hydrates (Fe2(SeO3)3•3H2O, Fe2(SeO3)3•5H2O) and the water content in the natural ferric selenite mandarinoite. Chemie der Erde. 2018. Vol. 78(2). P. 228-240.
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Any progress in our understanding of low-temperature mineral assemblages and of quantitative physico-chemical modeling of stability conditions of mineral phases, especially those containing toxic elements like selenium, strongly depends on the knowledge of structural and thermodynamic properties of coexisting mineral phases. Interrelation of crystal chemistry/structure and thermodynamic properties of selenium-containing minerals is not systematically studied so far and thus any essential generalization might be difficult, inaccurate or even impossible and erroneous. Disagreement even exists regarding the crystal chemistry of some natural and synthetic selenium-containing phases. Hence, a systematic study was performed by synthesizing ferric selenite hydrates and subsequent thermal analysis to examine the thermal stability of synthetic analogues of the natural hydrous ferric selenite mandarinoite and its dehydration and dissociation to unravel controversial issues regarding the crystal chemistry. Dehydration of synthesized analogues of mandarinoite starts at 56–87 °C and ends at 226–237 °C. The dehydration happens in two stages and two possible schemes of dehydration exist: (a) mandarinoite loses three molecules of water in the first stage of the dehydration (up to 180 °C) and the remaining two molecules of water will be lost in the second stage (>180 °C) or (b) four molecules of water will be lost in the first stage up to 180 °C and the last molecule of water will be lost at a temperature above 180 °C. Based on XRD measurements and thermal analyses we were able to deduce Fe 2(SeO 3) 3·(6-x)H 2O (x = 0.0–1.0) as formula of the hydrous ferric selenite mandarinoite. The total amount of water apparently affects the crystallinity, and possibly the stability of crystals: the less the x value, the higher crystallinity could be expected.
AB - Any progress in our understanding of low-temperature mineral assemblages and of quantitative physico-chemical modeling of stability conditions of mineral phases, especially those containing toxic elements like selenium, strongly depends on the knowledge of structural and thermodynamic properties of coexisting mineral phases. Interrelation of crystal chemistry/structure and thermodynamic properties of selenium-containing minerals is not systematically studied so far and thus any essential generalization might be difficult, inaccurate or even impossible and erroneous. Disagreement even exists regarding the crystal chemistry of some natural and synthetic selenium-containing phases. Hence, a systematic study was performed by synthesizing ferric selenite hydrates and subsequent thermal analysis to examine the thermal stability of synthetic analogues of the natural hydrous ferric selenite mandarinoite and its dehydration and dissociation to unravel controversial issues regarding the crystal chemistry. Dehydration of synthesized analogues of mandarinoite starts at 56–87 °C and ends at 226–237 °C. The dehydration happens in two stages and two possible schemes of dehydration exist: (a) mandarinoite loses three molecules of water in the first stage of the dehydration (up to 180 °C) and the remaining two molecules of water will be lost in the second stage (>180 °C) or (b) four molecules of water will be lost in the first stage up to 180 °C and the last molecule of water will be lost at a temperature above 180 °C. Based on XRD measurements and thermal analyses we were able to deduce Fe 2(SeO 3) 3·(6-x)H 2O (x = 0.0–1.0) as formula of the hydrous ferric selenite mandarinoite. The total amount of water apparently affects the crystallinity, and possibly the stability of crystals: the less the x value, the higher crystallinity could be expected.
KW - Differential scanning calorimetry
KW - Ferric selenite hydrates
KW - Mandarinoite
KW - Selenites
KW - Thermogravimetry
KW - SULFATES
KW - ARSENATES
KW - CRYSTAL-STRUCTURE
KW - STABILITY
KW - SULFIDE ORES
KW - FEATURES
KW - Therrnogravimetry
KW - THERMODYNAMICS
KW - DEHYDRATION
KW - OXIDATION ZONE
UR - http://www.scopus.com/inward/record.url?scp=85041622310&partnerID=8YFLogxK
UR - http://www.mendeley.com/research/thermal-behavior-ferric-selenite-hydrates-fe2seo333h2o-fe2seo335h2o-water-content-natural-ferric-sel
U2 - 10.1016/j.chemer.2018.01.002
DO - 10.1016/j.chemer.2018.01.002
M3 - Article
VL - 78
SP - 228
EP - 240
JO - Geochemistry
JF - Geochemistry
SN - 0009-2819
IS - 2
ER -
ID: 32801455