The crystal structure of the rare secondary lead mineral georgiadesite has been solved from single-crystal X-ray diffraction data (R = 0.071). The structure can be visualized in terms of alternating puckered (100) layers of [Pbφ6] octahedra and [Pbφ8] bicapped trigonal prisms (φ = generic anion). Lead also occurs in irregular, lopsided polyhedra. This structural study shows unambiguously that arsenic occurs as As3+ and not as As5+. The chemical formula of georgiadesite has therefore been revised, on structural grounds, to Pb4(AsO3)Cl4(OH).
|Autori:||PASERO M; VACCHIANO D|
|Titolo:||Crystal structure and revision of the chemical formula of georgiadesite, Pb4(AsO3)Cl4(OH)|
|Anno del prodotto:||2000|
|Digital Object Identifier (DOI):||10.1180/002646100549869|
|Appare nelle tipologie:||1.1 Articolo in rivista|