http://www.cnr.it/ontology/cnr/individuo/prodotto/ID208398

Tazzoliite: a new mineral with a pyrochlore-related structure from Euganei hills, Padova (Italy). (Articolo in rivista)

Type

Articolo in rivista (Classe)
Prodotto della ricerca (Classe)

Label

Tazzoliite: a new mineral with a pyrochlore-related structure from Euganei hills, Padova (Italy). (Articolo in rivista) (literal)

Anno

2012-01-01T00:00:00+01:00 (literal)

Alternative label

Camara F. [1]; Nestola F. [2]; Bindi L. [3]; Guastoni A. [4]; Zorzi F. [2]; Peruzzo L. [5]; Pedron D. [6] (2012)
Tazzoliite: a new mineral with a pyrochlore-related structure from Euganei hills, Padova (Italy).
in Mineralogical magazine (Online); Mineralogical Society of Great Britain and Ireland, LONDON (Regno Unito)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Camara F. [1]; Nestola F. [2]; Bindi L. [3]; Guastoni A. [4]; Zorzi F. [2]; Peruzzo L. [5]; Pedron D. [6] (literal)

Pagina inizio

827 (literal)

Pagina fine

838 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url

http://minmag.geoscienceworld.org/ (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

76 (literal)

Rivista

Mineralogical magazine (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

4 (literal)

Note

ISI Web of Science (WOS) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

[1] Dipartimento di Scienze della Terra, Universita` di Torino, Torino, Italy [2] Dipartimento di Geoscienze, Universita` di Padova, Padova, Italy [3] Dipartimento di Scienze della Terra, Universita` di Firenze, Firenze, Italy [4] Museo di Mineralogia, Universita` di Padova, Padova, Italy [5]C.N.R., Istituto di Geoscienze e Georisorse, Padova, Italy [6] Dipartimento di Scienze Chimiche, Universita` di Padova, Padova, Italy (literal)

Titolo

Tazzoliite: a new mineral with a pyrochlore-related structure from Euganei hills, Padova (Italy). (literal)

Abstract

Tazzoliite, ideally Ba2CaSr0.5Na0.5Ti2Nb3SiO17[PO2(OH)(2)](0.5), is a new mineral (IMA 2011-018) from Monte delle Basse, Euganei Hills, Galzignano Terme, Padova, Italy. It occurs as lamellar pale orange crystals, which are typically a few mu m thick and up to 0.4 mm long, closely associated with a diopsidic pyroxene and titanite. Tazzoliite is transparent. It has a white streak, a pearly lustre, is not fluorescent and has a hardness of 6 (Mohs' scale). The tenacity is brittle and the crystals have a perfect cleavage along {010}. The calculated density is 4.517 g cm(-3). Tazzoliite is biaxial (-) with 2V(meas) of similar to 50 degrees, it is not pleochroic and the average refractive index is 2.04. No twinning was observed. Electron-microprobe analyses gave the following chemical formula: (Ba1.93Ca1.20Sr0.52Na0.25Fe0.102+)(Sigma 4) (Nb2.88Ti2.05Ta0.07Zr0.01V0.015+)(Sigma 5.02)SiO17[(P0.13Si0.12S0.07)(Sigma 0.32)O-0.66(OH)(0.66)][F-0.09(OH)(0.23)](Sigma 0.32). Tazzoliite is orthorhombic, space group Fmmm, with unit-cell parameters a = 7.4116(3), b = 20.0632(8), c = 21.4402(8) angstrom, V = 3188.2(2) angstrom(3) and Z = 8. The crystal structure, obtained from single-crystal X-ray diffraction data, was refined to R-1(F-2) = 0.063. It consists of a framework of Nb(Ti) octahedra and BaO7 polyhedra sharing apexes or edges, and Si tetrahedra sharing apexes with Nb(Ti) octahedra and BaO7 polyhedra. The structure, which is related to the pyrochlore structure, contains three Nb(Ti) octahedra: two are Nb dominant and one is Ti dominant. Chains of A2O(8) polyhedra [A2 being occupied by Sr(Ca,Fe)] extend along [100] and are surrounded by Nb octahedra. Channels formed by six Nb(Ti) octahedra and two tetrahedra, or four A2O(8)(OH) polyhedra (A1 being occupied by Ba), alternate along [100]. The channels are partially occupied by [PO2(OH)(2)] in two possible mutually exclusive positions, alternating with fully occupied A3O(7) polyhedral pairs [A3 being occupied by Ca(Na)]. The seven strongest X-ray powder diffraction lines [d in angstrom (I/I-0) (hkl)] are: 3.66 (60) (044), 3.16 (30) (153), 3.05 (100) (204), 2.98 (25) (240), 2.84 (50) (064), 1.85 (25) (400) and 1.82 (25) (268). Raman spectra of tazzoliite were collected in the range 150-3700 cm(-1) and confirm the presence of OH groups. Tazzoliite is named in honour of Vittorio Tazzoli in recognition of his contributions to the fields of mineralogy and crystallography. (literal)

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