Original paper
The crystal structure of euchlorin, NaKCu3O (SO4)3
Scordari, Fernando; Stasi, Francesca
Neues Jahrbuch für Mineralogie - Abhandlungen Band 161 Heft 3 (1990), p. 241 - 253
20 references
published: Jun 7, 1990
DOI: 10.1127/njma/161/1990/241
ArtNo. ESP154016103001, Price: 29.00 €
Abstract
Euchlorin, NaKCu3O (SO4)3, occurring in fumaroles of Vesuvius (eruption 1868), is monoclinic, space group C 2/c, with a = 18.41 (5), b = 9.43 (3), c = 14.21 (5) Å, ß = 113.7 (3)°; V = 2258.89 Å3, Dm = 3.27, Dx = 3.28 g · cm-3; Z = 8. The crystal structure has been solved by direct methods and refined by full-matrix least-squares to an R factor of 0.048 using 655 reflection with I>3 σ(I). The euchlorin is a layered mineral. Its crystal structure consists of open mixed polyhedral layers parallel to (100) plane having chemical composition [Cu3O(SO4)]2+, built on one [CuO6]10-, two [CuO5]8- polyhedra and three [SO4]2- independent tetrahedra. Sodium and potassium, both seven-coordinated by oxygen-anions, and two [SO4]2- groups occupy the region between the layers making up an interlayer composition of [NaK(SO4)2]2-. Both structural parts combined result in the chemical formula quoted above. The good cleavage {100} is fully explained by the structure.
Keywords
Euchlorin • Crystal Structure