Rare sulfosalts from vulcano, aeolian islands, Italy: VII. Cl-bearing Galenobismotite
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Rare sulfosalts from vulcano, aeolian islands, Italy : VII. Cl-bearing Galenobismotite. / Pinto, Daniela; Balic Zunic, Tonci; Bonaccorsi, Elena; Borodaev, Yuri S.; Garavelli, Anna; Garbarino, Carlo; Makovicky, Emil; Mozgova, Nadezhda N.; Vurro, Filippo.
I: The Canadian Mineralogist, Bind 44, 2006, s. 443-457.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Rare sulfosalts from vulcano, aeolian islands, Italy
T2 - VII. Cl-bearing Galenobismotite
AU - Pinto, Daniela
AU - Balic Zunic, Tonci
AU - Bonaccorsi, Elena
AU - Borodaev, Yuri S.
AU - Garavelli, Anna
AU - Garbarino, Carlo
AU - Makovicky, Emil
AU - Mozgova, Nadezhda N.
AU - Vurro, Filippo
PY - 2006
Y1 - 2006
N2 - Cl-bearing galenobismutite (Cl ranging from 0.12 to 1.45 wt.%), discovered among high-temperature fumarole incrustations at "La Fossa" crater (Vulcano Island, Italy), has been chemically and structurally investigated. The mineral is commonly associated with bismuthinite, cannizzarite, lillianite, heyrovskýite and galena; rarely with kirkiite, vurroite and some other less characterized Pb(Bi)-sulfochlorides. Electron-microprobe investigations show that Cl-bearing galenobismutite from Vulcano has a wide compositional field (Pb/Bi atomic ratio ranging from 0.52 to 0.72). The statistical analysis of chemical data shows correlations between the main elements and chlorine, positive Pb vs Cl and negative Bi vs Cl, according to the coupled heterovalent substitution scheme: Pb2+ + Cl- « Bi3+ + S2-. The compositional variation of Cl-bearing galenobismutite can be represented by the general empirical formula Pb1+xBi2-x(S4-x-yClxSey) with 0 < x < 0.3 and 0 < y < 0.2, indicating the extent of departure from the ideal composition PbBi2S4 toward an increase of the Pb content and a decrease of Bi. The phase IV, synthetic analogue of galenobismutite in the system Pb-Bi-S, has the compositional field extending from ideal composition toward decreasing Pb (Pb/Bi atomic ratio 0.50 - 0.39). It reflects another type of substitution: 3Pb2+ à 2Bi3+ + ¿. X-ray single crystal investigations were performed on two selected crystals of Cl-bearing galenobismutite from Vulcano. The composition of galenobismutite controls the a and b unit-cell parameters, which increase with the increase of the Cl content. The structural refinements converge to the agreement R values of 3.10 % for 840 reflections [Fo > 4s(Fo)] and 1.49 % for 376 reflections [Fo > 4s(Fo)], respectively. The structure of Cl-bearing galenobismutite is topologically identical to that of Cl-free galenobismutite. The excess of Pb observed in Cl-bearing galenobismutite is incorporated in the trigonal prismatic M2gb and M3gb sites. No Pb for Bi substitution was observed for the octahedral position M1gb. No evidence of a preferential distribution of Cl among the anion positions was observed.
AB - Cl-bearing galenobismutite (Cl ranging from 0.12 to 1.45 wt.%), discovered among high-temperature fumarole incrustations at "La Fossa" crater (Vulcano Island, Italy), has been chemically and structurally investigated. The mineral is commonly associated with bismuthinite, cannizzarite, lillianite, heyrovskýite and galena; rarely with kirkiite, vurroite and some other less characterized Pb(Bi)-sulfochlorides. Electron-microprobe investigations show that Cl-bearing galenobismutite from Vulcano has a wide compositional field (Pb/Bi atomic ratio ranging from 0.52 to 0.72). The statistical analysis of chemical data shows correlations between the main elements and chlorine, positive Pb vs Cl and negative Bi vs Cl, according to the coupled heterovalent substitution scheme: Pb2+ + Cl- « Bi3+ + S2-. The compositional variation of Cl-bearing galenobismutite can be represented by the general empirical formula Pb1+xBi2-x(S4-x-yClxSey) with 0 < x < 0.3 and 0 < y < 0.2, indicating the extent of departure from the ideal composition PbBi2S4 toward an increase of the Pb content and a decrease of Bi. The phase IV, synthetic analogue of galenobismutite in the system Pb-Bi-S, has the compositional field extending from ideal composition toward decreasing Pb (Pb/Bi atomic ratio 0.50 - 0.39). It reflects another type of substitution: 3Pb2+ à 2Bi3+ + ¿. X-ray single crystal investigations were performed on two selected crystals of Cl-bearing galenobismutite from Vulcano. The composition of galenobismutite controls the a and b unit-cell parameters, which increase with the increase of the Cl content. The structural refinements converge to the agreement R values of 3.10 % for 840 reflections [Fo > 4s(Fo)] and 1.49 % for 376 reflections [Fo > 4s(Fo)], respectively. The structure of Cl-bearing galenobismutite is topologically identical to that of Cl-free galenobismutite. The excess of Pb observed in Cl-bearing galenobismutite is incorporated in the trigonal prismatic M2gb and M3gb sites. No Pb for Bi substitution was observed for the octahedral position M1gb. No evidence of a preferential distribution of Cl among the anion positions was observed.
KW - Faculty of Science
KW - Italien
KW - vulkan ø
KW - krystal strukturer
KW - Cl-bearing galenobismutite
KW - Italy
KW - Vulcano Island
KW - fumaroles
KW - crystal structure
KW - Pb-Bi sulfosalt
U2 - 10.2113/gscanmin.44.2.443
DO - 10.2113/gscanmin.44.2.443
M3 - Journal article
VL - 44
SP - 443
EP - 457
JO - Canadian Mineralogist
JF - Canadian Mineralogist
SN - 0008-4476
ER -
ID: 1696741