Dataset Information

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 by the non-bridging sulfate group S1O4. The [Na(SO4)2](3-) chain features an unusual centrosymmetric group formed by two NaO6 octa-hedra and two S2O4 tetra-hedra sharing five adjacent edges, one between two NaO6 octa-hedra and two each between the resulting double octa-hedron and two S2O4 tetra-hedra. These groups are then linked into a double-stranded chain via corner-sharing between NaO6 octa-hedra and S2O4 tetra-hedra. The S1O4 group, attached to Na in the terminal position, completes the chains. The [Al(H2O)6](3+) octa-hedron (?Al-O? = 1.885?(11)?Å) donates 12 comparatively strong hydrogen bonds (O?O = 2.6665?(14) - 2.7971?(15)?Å) to the sulfate O atoms of three neighbouring [Na(SO4)2](3-) chains, helping to connect them in three dimensions, but with a prevalence parallel to (010), the cleavage plane of the mineral. Compared with the previous work on tamarugite, the bond precision of Al-O bond lengths as an example improved from 0.024 to 0.001?Å.

SUBMITTER: Mereiter K

PROVIDER: S-EPMC3790334 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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

Mereiter Kurt K

Acta crystallographica. Section E, Structure reports online 20130921 Pt 10

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] ...[more]

PMID: 24098156

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Project description:The aim of the present investigation was to verify the effect of H2O2-induced oxidative stress on SO4= uptake through Band 3 protein, responsible for Cl-/HCO3- as well as for cell membrane deformability, due to its cross link with cytoskeletal proteins. The role of cytoplasmic proteins binding to Band 3 protein has been also considered by assaying H2O2 effects on hemoglobin-free resealed ghosts of erythrocytes. Oxidative conditions were induced by 30 min exposure of human erythrocytes to different H2O2 concentrations (10 to 300 ?M), with or without GSH (glutathione, 2 mM) or curcumin (10 ?M), compounds with proved antioxidant properties. Since SO4= influx through Band 3 protein is slower and better controllable than Cl- or HCO3- exchange, the rate constant for SO4= uptake was measured to prove anion transport efficiency, while MDA (malondialdehyde) levels and -SH groups were estimated to quantify the effect of oxidative stress. H2O2 induced a significant decrease in rate constant for SO4= uptake at both 100 and 300 ?M H2O2. This reduction, observed in erythrocytes but not in resealed ghosts and associated to increase in neither MDA levels nor in -SH groups, was impaired by both curcumin and GSH, whereas only curcumin effectively restored H2O2-induced changes in erythrocytes shape. Our results show that: i) 30 min exposure to 300 ?M H2O2 reduced SO4= uptake in human erythrocytes; ii) oxidative damage was revealed by the reduction in rate constant for SO4= uptake, but not by MDA or -SH groups levels; iii) the damage was produced via cytoplasmic components which cross link with Band 3 protein; iv) the natural antioxidant curcumin may be useful in protecting erythrocytes from oxidative injury; v) SO4= uptake through Band 3 protein may be reasonably suggested as a tool to monitor erythrocytes function under oxidative conditions possibly deriving from alcohol consumption, use of drugs, radiographic contrast media administration, hyperglicemia or neurodegenerative diseases.

Dataset Information

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

Publications

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

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