| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Bonaccorsi, Elena
University of Pisa
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (9/9 displayed)
- 2020Derbylite and graeserite from the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy: occurrence and crystal-chemistrycitations
- 2017Lead-antimony sulfosalts from Tuscany (Italy). XXI. Bernarlottiite, Pb12(As10Sb6)Σ16S36, a new N = 3.5 member of the sartorite homologous series from the Ceragiola marble quarry: Occurrence and crystal structurecitations
- 2014Cation exchange in clinotobermorite: preliminary results
- 2013Lead-antimony sulfosalts from Tuscany (Italy). XIV. Disulfodadsonite, Pb11Sb13S30(S2)0.5, a new mineral from the Ceragiola marble quarry, Apuan Alps: occurrence and crystal structure.citations
- 2012Lead-antimony sulfosalts from Tuscany (Italy). XII. Boscardinite, TlPb4(Sb7As2)S18, a new mineral species from the Monte Arsiccio mine: occurrence and crystal structurecitations
- 2008Double wollastonite chains: topological/conformational varieties, polytypic forms, isotypic compoundscitations
- 2008The crystal structure of vurroite, Pb20Sn2(Bi,As)22S54Cl6: OD-character, polytypism, twinning, and modular descriptioncitations
- 2001Microsommite: crystal-chemistry, phase transitions, Ising model and Monte Carlo simulations
- 2001The real structure of tobermorite 11A: normal and anomalous forms, OD character and polytypic modificationscitations
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article
Derbylite and graeserite from the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy: occurrence and crystal-chemistry
Abstract
<jats:title>Abstract</jats:title><jats:p>New occurrences of derbylite, Fe<jats:sub><jats:italic>x</jats:italic></jats:sub><jats:sup>2+</jats:sup>Fe<jats:sup>3+</jats:sup><jats:sub>4–2<jats:italic>x</jats:italic></jats:sub>Ti<jats:sup>4+</jats:sup><jats:sub>3+<jats:italic>x</jats:italic></jats:sub>Sb<jats:sup>3+</jats:sup>O<jats:sub>13</jats:sub>(OH), and graeserite, Fe<jats:sub><jats:italic>x</jats:italic></jats:sub><jats:sup>2+</jats:sup>Fe<jats:sup>3+</jats:sup><jats:sub>4–2<jats:italic>x</jats:italic></jats:sub>Ti<jats:sup>4+</jats:sup><jats:sub>3+<jats:italic>x</jats:italic></jats:sub>As<jats:sup>3+</jats:sup>O<jats:sub>13</jats:sub>(OH), have been identified in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. Derbylite occurs as prismatic to acicular black crystals in carbonate veins. Iron and Ti are replaced by V (up to 0.29 atoms per formula unit, apfu) and minor Cr (up to 0.04 apfu). Mössbauer spectroscopy confirmed the occurrence of Fe<jats:sup>2+</jats:sup> (up to 0.73 apfu), along with Fe<jats:sup>3+</jats:sup>. The Sb/(As+Sb) atomic ratio ranges between 0.73 and 0.82. Minor Ba and Pb (up to 0.04 apfu) substitute. Derbylite is monoclinic, space group <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>m</jats:italic>, with unit-cell parameters <jats:italic>a</jats:italic> = 7.1690(3), <jats:italic>b</jats:italic> = 14.3515(7), <jats:italic>c</jats:italic> = 4.9867(2) Å, β = 104.820(3)° and <jats:italic>V</jats:italic> = 495.99(4) Å<jats:sup>3</jats:sup>. The crystal structure was refined to <jats:italic>R</jats:italic><jats:sub>1</jats:sub> = 0.0352 for 1955 reflections with <jats:italic>F</jats:italic><jats:sub>o</jats:sub> > 4σ(<jats:italic>F</jats:italic><jats:sub>o</jats:sub>). Graeserite occurs as prismatic to tabular black crystals, usually twinned, in carbonate veins or as porphyroblasts in schist. Graeserite in the first kind of assemblage is V rich (up to 0.66 apfu), and V poor in the second kind (0.03 apfu). Along with minor Cr (up to 0.06 apfu), this element replaces Fe and Ti. The occurrence of Fe<jats:sup>2+</jats:sup> (up to 0.68 apfu) is confirmed by Mössbauer spectroscopy. Arsenic is dominant over Sb and detectable amounts of Ba and Pb have been measured (up to 0.27 apfu). Graeserite is monoclinic, space group <jats:italic>C</jats:italic>2/<jats:italic>m</jats:italic>, with unit-cell parameters for two samples: <jats:italic>a</jats:italic> = 5.0225(7), <jats:italic>b</jats:italic> = 14.3114(18), <jats:italic>c</jats:italic> = 7.1743(9) Å, β = 104.878(3)°, <jats:italic>V</jats:italic> = 498.39(11) Å<jats:sup>3</jats:sup>; and <jats:italic>a</jats:italic> = 5.0275(4), <jats:italic>b</jats:italic> = 14.2668(11), <jats:italic>c</jats:italic> = 7.1663(5) Å, β = 105.123(4)° and <jats:italic>V</jats:italic> = 496.21(7) Å<jats:sup>3</jats:sup>. The crystal structures were refined to <jats:italic>R</jats:italic><jats:sub>1</jats:sub> = 0.0399 and 0.0237 for 428 and 1081 reflections with <jats:italic>F</jats:italic><jats:sub>o</jats:sub> > 4σ(<jats:italic>F</jats:italic><jats:sub>o</jats:sub>), respectively. Derbylite and graeserite are homeotypic. They share the same tunnel structure, characterised by an octahedral framework and cuboctahedral cavities, hosting (As/Sb)O<jats:sub>3</jats:sub> groups and (Ba/Pb) atoms.</jats:p>