ISSN:
1063-7745
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract The crystal structure of α-RbB3O5 was refined by the Rietveld method with due regard for anisotropic vibrations of rubidium atoms to R p = 2.93, R wp = 3.80, R B = 2.53, R F = 2.84, and s = 1.54. The compound is isostructural to CsB3O5: it is orthorhombic, sp. gr. P212121, a = 8.209(1), b = 10.092(1), c = 5.382(1) Å, and V = 445.9 Å 3. The framework structure is formed by the boron-oxygen [B 2 III BIVO5] − rings consisting of two [BO3]-triangles and a [BO4]-tetrahedron. The rings are linked to form systems of helical chains running along the twofold screw axes parallel 21 to the a-and b-axes and infinite channels parallel to the a-and c-axes, which accommodate Rb atoms. The data were collected on an ADP-2 diffractometer [CuK α radiation, Ni-filter, 12.00° 〈 2θ 〈 110.00°, a step in 2θ equal to 0.02°, count time 8 s per step, and 711 reflections α1 + α2)]. All the calculations were performed using version 3.3 of the WYRIET program. The comparison of the structures of α-and β-RbB3O5 and CsB3O5 revealed that the type of deformations in the framework structures of alkali-metal borates due to the changes of the temperature or the substitution of cations is determined by the role played by metal atoms, and especially, by large and heavy ions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.1306564
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