| MAJZLAN, Juraj, Biljana LAZIC, Thomas ARMBRUSTER, Michel B JOHNSON, Mary Anne WHITE, Robert Allan FISHER, Jakub PLÁŠIL, Jan LOUN, Radek ŠKODA and Milan NOVÁK. Crystal structure, thermodynamic properties, and paragenesis of bukovskyite, Fe-2(AsO4)(SO4)(OH)center dot 9H(2)O. JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES. SENDAI: JAPAN ASSOC MINERALOGICAL SCIENCES, 2012, vol. 107, No 3, p. 133-148. ISSN 1345-6296. Available from: https://dx.doi.org/10.2465/jmps.110930. |
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@article{1092115,
author = {Majzlan, Juraj and Lazic, Biljana and Armbruster, Thomas and Johnson, Michel B and White, Mary Anne and Fisher, Robert Allan and Plášil, Jakub and Loun, Jan and Škoda, Radek and Novák, Milan},
article_location = {SENDAI},
article_number = {3},
doi = {http://dx.doi.org/10.2465/jmps.110930},
keywords = {Bukovskyite; Crystal structure; Thermodynamics; Paragenesis},
language = {eng},
issn = {1345-6296},
journal = {JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES},
title = {Crystal structure, thermodynamic properties, and paragenesis of bukovskyite, Fe-2(AsO4)(SO4)(OH)center dot 9H(2)O},
volume = {107},
year = {2012}
}
TY - JOUR
ID - 1092115
AU - Majzlan, Juraj - Lazic, Biljana - Armbruster, Thomas - Johnson, Michel B - White, Mary Anne - Fisher, Robert Allan - Plášil, Jakub - Loun, Jan - Škoda, Radek - Novák, Milan
PY - 2012
TI - Crystal structure, thermodynamic properties, and paragenesis of bukovskyite, Fe-2(AsO4)(SO4)(OH)center dot 9H(2)O
JF - JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES
VL - 107
IS - 3
SP - 133-148
EP - 133-148
PB - JAPAN ASSOC MINERALOGICAL SCIENCES
SN - 13456296
KW - Bukovskyite
KW - Crystal structure
KW - Thermodynamics
KW - Paragenesis
N2 - Bukovskyite is a relatively rare secondary ferric arsenate-sulfate. At the type locality near the municipality of Kutna Hora (Czech Republic), it is the main secondary mineral in the medieval dumps, where it occurs in enormous amounts and forms nodules of prodigious dimensions. We investigated the mineral bukovskyite and the type locality in detail to understand the abundance of the mineral at this locality. The crystal structure of bukovskyite was solved for bukovskyite crystals from Grossvoigtsberg (Germany) and found to be of the space group P (I) over bar with a final R factor of 5.08% from 2403 reflections. The lattice parameters at room temperature are a = 7.549(1) angstrom, b = 10.305(1) angstrom, c = 10.914(2) angstrom, alpha = 115.136(3)degrees, beta = 99.798(3)degrees, and gamma = 92.864(3)degrees. The structure consists of octahedral-tetrahedral Fe-arsenate chains. Sulfate tetrahedra are bonded to the chains and free H2O molecules via a complicated network of hydrogen bonds. Calorimetric measurements (acid-solution calorimetry at T = 298.15 K and relaxation calorimetry yielded heat capacities from T = 0.4 K to 300 K) gave an enthalpy of formation of -4742.4 +/- 3.8 kJ.mol(-1) and standard entropy of 615.2 +/- 6.9 J.mol(-l).K-1. A combination of these values gives a Gibbs free energy of formation of -3968.9 +/- 4.3 kJ.mol(-1) and aqueous solubility product (log K) of -30.627. Bukovskyite is metastable with respect to scorodite; if scorodite is not considered in the thermodynamic calculations, a stability field of bukovskyite appears at low pH and high sulfate and arsenate activity. Field observations showed that bukovskyite occurs in dumps where the space between the rock fragments is filled by clays. Bukovskyite crystallizes from Fe-As-S-rich gels that replace Si-Al gels. The exact mechanisms that control the entire process are not clear but will be the subject of further studies.
ER -
MAJZLAN, Juraj, Biljana LAZIC, Thomas ARMBRUSTER, Michel B JOHNSON, Mary Anne WHITE, Robert Allan FISHER, Jakub PLÁŠIL, Jan LOUN, Radek ŠKODA and Milan NOVÁK. Crystal structure, thermodynamic properties, and paragenesis of bukovskyite, Fe-2(AsO4)(SO4)(OH)center dot 9H(2)O. \textit{JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES}. SENDAI: JAPAN ASSOC MINERALOGICAL SCIENCES, 2012, vol.~107, No~3, p.~133-148. ISSN~1345-6296. Available from: https://dx.doi.org/10.2465/jmps.110930.
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