| Texto completo | |
| Autor(es): Mostrar menos - |
Kolitsch, U.
[1, 2]
;
Atencio, D.
[3]
;
Chukanov, N. V.
[4]
;
Zubkova, N. V.
[5]
;
Menezes Filho, L. A. D.
[6]
;
Coutinho, J. M. V.
[3]
;
Birch, W. D.
[7]
;
Schluter, J.
[8]
;
Pohl, D.
[9]
;
Kampf, A. R.
[10]
;
Steele, I. M.
[11]
;
Favreau, G.
;
Nasdala, L.
[2]
;
Mockel, S.
;
Giester, G.
[2]
;
Pushcharovsky, D. Yu
[5]
Número total de Autores: 16
|
| Afiliação do(s) autor(es): Mostrar menos - | [1] Nat Hist Museum, Mineral Petrog Abt, A-1010 Vienna - Austria
[2] Univ Vienna, Inst Mineral & Kristallog, A-1090 Vienna - Austria
[3] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo - Brazil
[4] Inst Problems Chem Phys, Chernogolovka 142432, Moscow Oblast - Russia
[5] Moscow MV Lomonosov State Univ, Fac Geol, Moscow 119899 - Russia
[6] Univ Fed Minas Gerais, Inst Geociencias, BR-3127901 Belo Horizonte, MG - Brazil
[7] Museum Victoria, Dept Mineral, Melbourne, Vic 3001 - Australia
[8] Univ Hamburg, Mineral Museum, D-20146 Hamburg - Germany
[9] Univ Hamburg, Mineral Petrog Inst, D-20146 Hamburg - Germany
[10] Nat Hist Museum Los Angeles Cty, Dept Mineral Sci, Los Angeles, CA 90007 - USA
[11] Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 - USA
Número total de Afiliações: 11
|
| Tipo de documento: | Artigo Científico |
| Fonte: | MINERALOGICAL MAGAZINE; v. 74, n. 3, p. 469-486, JUN 2010. |
| Citações Web of Science: | 7 |
| Resumo | |
Bendadaite, ideally Fe(2+)Fe(2)(3+)(AsO(4))(2)(OH)(2 center dot).4H(2)O, is a new member of the arthurite group It was found as a weathering product of arsenopyrite on a single hand specimen from the phosphate pegmatite Bendada. central Portugal (type locality) Co-type locality is the granite pegmatite of La via do Almerindo (Almerindo mine), Linopolis, Divmo das Laranjeiras county, Minas Gerais, Brazil Further localities are the Vein Negra mine, Copiapo province, Chile, mid-East, Bou Azzer district, Morocco, and Para Inferida yard, Fenugu Sibirt mine, Gonnosfanadiga, Medio Campidano Province, Sardinia. Italy Type bendadaite occurs as blackish green to dark brownish tufts (<0 1 mm long) and flattened radiating aggregates. in intimate association with an intermediate member of the scorodite-mansfieldite series It is monoclinic. space group P2(l/c). with a = 10 239(3) angstrom. b = 9 713(2) angstrom, c = 5 552(2) angstrom. beta = 94 11(2)degrees. = 550 7(2) angstrom(3). Z = 2 Electron-microprobe analysis yielded (wt %). CaO 0 04, MnO 0 03. CuO 006, ZnO 004. Fe(2)O(3) (total) 43 92, Al(2)O(3) 115. SnO(2) 0 10, As(2)O(5) 43 27. P(2)O(5) 1 86, SO(3) 0.03 The empirical formula is (Fe(0 52)(2+)Fe(0 32)(3+)rectangle(0 16))(Sigma 1 00)(Fe(1 89)(3+)Al(0 11))(Sigma 2 00)(As(1 87)P(0 13))(Sigma 2 00)O(8)(OH)(2 00) 4H(2)O based. CM 2(As,P) and assuming ideal 80, 2(OH), 4H2O and complete occupancy of the ferric on site by Fe(3+) and Al Optically, bendadaite is biaxial, positive, 2V(est) = 85+/-4 degrees, 2V(eale) = 88 degrees, with alpha 1 734(3). 13 1 759(3), 7 1 787(4) Pleochrosim is medium strong X pale reddish brown. Y yellowish brown, Z dark yellowish brown. absorption Z > V > X, optical dispersion weak, r > v. Optical axis plane Is parallel to (010), with X approximately parallel to a and Z nearly parallel to c Bendadaite has vitreous to sub-adamantine luster, is translucent and non-fluorescent It is brittle, shows irregular fracture and a good cleavage parallel to 1010] 3 15 0 10 g/cm(3), 3 193 g/cm3 (for the empirical formula) The five strongest powder diffraction lines {[}d in angstrom (I)(hkl] are 10 22 (10)(100), 7 036 (8)(110), 4 250 (5)(11 I), 2 865 (4)(311), 4 833 (3)(020,011) The d spacings are very similar to those of its Zn analogue, ojelaite The crystal structure of bendadaite was solved and refined using a crystal from the co-type locality with the composition (Fe(0 95)(2+)rectangle(0 05))(Sigma 1 00)(Fe(1 80)(3+)Al(0 20))Sigma(2 00)(As(1 48)P(0 52))(Sigma 2 00)O(8)) (OH)(2) 4H(2)O (R = 16%) and confirms an arthurite-type atomic arrangement (AU) | |
| Processo FAPESP: | 05/53741-1 - Os novos minerais brasileiros: caracterização e descrição |
| Beneficiário: | Daniel Atencio |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 09/09125-5 - Minerais novos do Brasil: caracterização cristaloquímica e síntese |
| Beneficiário: | Daniel Atencio |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |