Original paper

The crystal structure of chiavennite

Tazzoli, Vittorio; Domeneghetti, M . Chiara; Mazzi, Fiοrenzο; Cannillo, Eliο

European Journal of Mineralogy Volume 7 Number 6 (1995), p. 1339 - 1344

17 references

published: Dec 27, 1995
manuscript accepted: Jul 11, 1995
manuscript received: Feb 21, 1995

DOI: 10.1127/ejm/7/6/1339

BibTeX file

ArtNo. ESP147050706006, Price: 29.00 €

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Abstract Chiavennite, CaMn(BeOH)2Si5O13-2H2O, is orthorhombic, space group Pnab, a = 8.729(5), b = 31.326(11), c = 4.903(2), Z = 4. The structure was determined by direct methods, using 1976 independent reflections, measured with an automated X-ray single crystal diffractometer. The anisotropic least-squares refinement led to a final discrepancy index R = 0.041 for the 999 observed reflections with I ≥ 5α(I). Chiavennite has an interrupted framework of four-connected [SiO4] and three-connected [BeO4] tetrahedra, which consists of zig-zag chains combined with a 4.82 2D net. The framework density FD = 20.9 T/1000 Å3 classifies chiavennite as a zeolite. Nine-membered rings of tetrahedra form one-dimensional system of channels parallel to [001] with free diameters of 3.3 x 4.3 Å. The extra-framework cations are Mn, in 6-fold coordination (octahedron, four O + two OH) and Ca, in 8-fold coordination (square antiprism, four O + two OH + two H2O). Ca and H2O are located in the channels


chiavennitecrystal-structurezeoliteinterrupted framework