Redetermination of tamarugite, NaAl(SO4)2·6H2O.

ABSTRACT: The crystal structure of tamarugite [sodium aluminium bis-(sulfate) hexa-hydrate] was redetermined from a single crystal from Mina Alcaparossa, near Cerritos Bayos, southwest of Calama, Chile. In contrast to the previous work [Robinson & Fang (1969 ▶). Am. Mineral. 54, 19-30], all non-H atoms were refined with anisotropic displacement parameters and H-atoms were located by difference Fourier methods and refined from X-ray diffraction data. The structure is built up from nearly regular [Al(H2O)6](3+) octa-hedra and infinite double-stranded chains [Na(SO4)2](3-) that extend parallel to [001]. The Na(+) cation has a strongly distorted octa-hedral coordination by sulfate O atoms [Na-O = 2.2709 (11) - 2.5117 (12) Å], of which five are furnished by the chain-building sulfate group S2O4 and one b

SUBMITTER: Mereiter K 

PROVIDER: S-EPMC3790334 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature