| 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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Spratt, John
Natural History Museum
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (11/11 displayed)
- 2022Polytypism in mcalpineite: a study of natural and synthetic Cu3TeO6citations
- 2021Kernowite, Cu<sub>2</sub>Fe(AsO<sub>4</sub>)(OH)<sub>4</sub>⋅4H<sub>2</sub>O, the Fe<sup>3+</sup>-analogue of liroconite from Cornwall, UKcitations
- 2021Oscillatory- and sector-zoned pyrochlore from carbonatites of the Kerimasi volcano, Gregory rift, Tanzaniacitations
- 2021Elucidating the natural–synthetic mismatch of Pb2+Te4+O3: The redefinition of fairbankite to Pb122+(Te4+O3)11(SO4)citations
- 2021Native tungsten from the Bol'shaya Pol'ya river valley and Mt Neroyka, Russia
- 2021Wildcatite, CaFe3+Te6+O5(OH), the second new tellurate mineral from the Detroit district, Juab County, Utahcitations
- 2021Hybridization of Alkali Basaltic Magmas: a Case Study of the Ogol Lavas from the Laetoli Area, Crater Highlands (Tanzania)citations
- 2019Dokuchaevite, Cu<sub>8</sub>O<sub>2</sub>(VO<sub>4</sub>)<sub>3</sub>Cl<sub>3</sub>, a new mineral with remarkably diverse Cu<sup>2+</sup> mixed-ligand coordination environmentscitations
- 2019The crystal structures of the mixed-valence tellurium oxysalts tlapallite, (Ca,Pb)<sub>3</sub>CaCu<sub>6</sub>[Te<sup>4+</sup><sub>3</sub>Te<sup>6+</sup>O<sub>12</sub>]<sub>2</sub>(Te<sup>4+</sup>O<sub>3</sub>)<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub>·3H<sub>2</sub>O, and carlfriesite, CaTe<sup>4+</sup><sub>2</sub>Te<sup>6+</sup>O<sub>8</sub>citations
- 2015Barrydawsonite-(Y), Na<sub>1.5</sub>CaY<sub>0.5</sub>Si<sub>3</sub>O<sub>9</sub>H: a new pyroxenoid of the pectolite–serandite groupcitations
- 2013Diegogattaite, Na<sub>2</sub>CaCu<sub>2</sub>Si<sub>8</sub>O<sub>2</sub>0·H<sub>2</sub>O: a new nanoporous copper sheet silicate from Wessels Mine, Kalahari Manganese Fields, Republic of South Africacitations
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article
The crystal structures of the mixed-valence tellurium oxysalts tlapallite, (Ca,Pb)<sub>3</sub>CaCu<sub>6</sub>[Te<sup>4+</sup><sub>3</sub>Te<sup>6+</sup>O<sub>12</sub>]<sub>2</sub>(Te<sup>4+</sup>O<sub>3</sub>)<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub>·3H<sub>2</sub>O, and carlfriesite, CaTe<sup>4+</sup><sub>2</sub>Te<sup>6+</sup>O<sub>8</sub>
Abstract
<jats:title>ABSTRACT</jats:title><jats:p>The crystal structure of tlapallite has been determined using single-crystal X-ray diffraction and supported by electron probe micro-analysis, powder diffraction and Raman spectroscopy. Tlapallite is trigonal, space group<jats:italic>P</jats:italic>321, with<jats:italic>a</jats:italic>= 9.1219(17) Å,<jats:italic>c</jats:italic>= 11.9320(9) Å and<jats:italic>V</jats:italic>= 859.8(3) Å<jats:sup>3</jats:sup>, and was refined to<jats:italic>R</jats:italic><jats:sub>1</jats:sub>= 0.0296 for 786 reflections with<jats:italic>I</jats:italic>> 2σ(<jats:italic>I</jats:italic>). This study resulted from the discovery of well-crystallised tlapallite at the Wildcat prospect, Utah, USA. The chemical formula of tlapallite has been revised to (Ca,Pb)<jats:sub>3</jats:sub>CaCu<jats:sub>6</jats:sub>[Te<jats:sup>4+</jats:sup><jats:sub>3</jats:sub>Te<jats:sup>6+</jats:sup>O<jats:sub>12</jats:sub>]<jats:sub>2</jats:sub>(Te<jats:sup>4+</jats:sup>O<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>(SO<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>·3H<jats:sub>2</jats:sub>O, or more simply (Ca,Pb)<jats:sub>3</jats:sub>CaCu<jats:sub>6</jats:sub>Te<jats:sup>4+</jats:sup><jats:sub>8</jats:sub>Te<jats:sup>6+</jats:sup><jats:sub>2</jats:sub>O<jats:sub>30</jats:sub>(SO<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>·3H<jats:sub>2</jats:sub>O, from H<jats:sub>6</jats:sub>(Ca,Pb)<jats:sub>2</jats:sub>(Cu,Zn)<jats:sub>3</jats:sub>(TeO<jats:sub>3</jats:sub>)<jats:sub>4</jats:sub>(TeO<jats:sub>6</jats:sub>)(SO<jats:sub>4</jats:sub>). The tlapallite structure consists of layers containing distorted Cu<jats:sup>2+</jats:sup>O<jats:sub>6</jats:sub>octahedra, Te<jats:sup>6+</jats:sup>O<jats:sub>6</jats:sub>octahedra and Te<jats:sup>4+</jats:sup>O<jats:sub>4</jats:sub>disphenoids (which together form the new mixed-valence phyllotellurate anion [Te<jats:sup>4+</jats:sup><jats:sub>3</jats:sub>Te<jats:sup>6+</jats:sup>O<jats:sub>12</jats:sub>]<jats:sup>12−</jats:sup>), Te<jats:sup>4+</jats:sup>O<jats:sub>3</jats:sub>trigonal pyramids and CaO<jats:sub>8</jats:sub>polyhedra. SO<jats:sub>4</jats:sub>tetrahedra, Ca(H<jats:sub>2</jats:sub>O)<jats:sub>3</jats:sub>O<jats:sub>6</jats:sub>polyhedra and H<jats:sub>2</jats:sub>O groups fill the space between the layers. Tlapallite is only the second naturally occurring compound containing tellurium in both the 4<jats:sup>+</jats:sup>and 6<jats:sup>+</jats:sup>oxidation states with a known crystal structure, the other being carlfriesite, CaTe<jats:sup>4+</jats:sup><jats:sub>2</jats:sub>Te<jats:sup>6+</jats:sup>O<jats:sub>8</jats:sub>. Carlfriesite is the predominant secondary tellurium mineral at the Wildcat prospect. We also present an updated structure for carlfriesite, which has been refined to<jats:italic>R</jats:italic><jats:sub>1</jats:sub>= 0.0230 for 874 reflections with<jats:italic>I</jats:italic>> 2σ(<jats:italic>I</jats:italic>). This updated structural refinement improves upon the one reported previously by refining all atoms anisotropically and presenting models of bond valence and Te<jats:sup>4+</jats:sup>secondary bonding.</jats:p>