Crystals of challacolloite, KPb(2)Cl(5), and hephaistosite, TlPb(2)Cl(5), from volcanic sublimates formed on the crater rim of the "La Fossa Crater" at Vulcano, Aeolian Archipelago, Italy, were investigated. Chemical compositions were (K(0.93)Tl(0. 02))(Sigma=0.95) Pb(2.04) (Cl(4.90)Br(0.11))(Sigma=5.01) and Tl(0.94)Pb(2.01)(Cl(4.91)Br(0.14) )(Sigma=5.05), respectively. Single crystal X-ray measurements showed monoclinic symmetry for both phases, space group P2(1)/c, with the following unit-cell parameters. a = 8.8989(4), b = 7.9717(5), c = 12.5624(8) angstrom, beta = 90.022(4)degrees, V = 891.2(1) angstrom(3), Z = 4 (challacolloite) and a = 9.0026(6), b = 7.9723(6), c = 12.5693(9) angstrom, beta = 90.046 (4)degrees, V = 902.1(1) angstrom(3), Z = 4 (hephaistosite). The structure refinements converge to R = 3.99% and R = 3.86%, respectively. The effects of Br <-> Cl and K <-> Tl substitutions on the structure of these natural compounds have been discussed.

The role of the minor substitutions in the crystal structure of natural challacolloite, K2Pb2Cl5, and hephaistosite, TlPb2Cl5, from Vulcano (Aeolian Archipelago, Italy)

PINTO, DANIELA;GARAVELLI, Anna;
2009-01-01

Abstract

Crystals of challacolloite, KPb(2)Cl(5), and hephaistosite, TlPb(2)Cl(5), from volcanic sublimates formed on the crater rim of the "La Fossa Crater" at Vulcano, Aeolian Archipelago, Italy, were investigated. Chemical compositions were (K(0.93)Tl(0. 02))(Sigma=0.95) Pb(2.04) (Cl(4.90)Br(0.11))(Sigma=5.01) and Tl(0.94)Pb(2.01)(Cl(4.91)Br(0.14) )(Sigma=5.05), respectively. Single crystal X-ray measurements showed monoclinic symmetry for both phases, space group P2(1)/c, with the following unit-cell parameters. a = 8.8989(4), b = 7.9717(5), c = 12.5624(8) angstrom, beta = 90.022(4)degrees, V = 891.2(1) angstrom(3), Z = 4 (challacolloite) and a = 9.0026(6), b = 7.9723(6), c = 12.5693(9) angstrom, beta = 90.046 (4)degrees, V = 902.1(1) angstrom(3), Z = 4 (hephaistosite). The structure refinements converge to R = 3.99% and R = 3.86%, respectively. The effects of Br <-> Cl and K <-> Tl substitutions on the structure of these natural compounds have been discussed.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/132314
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 12
social impact