Variable temperature x-ray crystal structure analysis of a type I langbeinite: Rb2Cd2(SO4)(3)


Autoria(s): Nalini, G; Row, Guru TN
Data(s)

01/11/2002

Resumo

The structure of a type I langbeinite, Rb2Cd2(SO4)(3), displays three different phases, cubic with a = 10.378(5) Angstrom (space group P2(1)3) at room temperature, monoclinic at 120 K with a = 10.328(3), b = 10.322(3), c = 10.325(3) Angstrom, beta = 89.975(1)degrees (space group P2(1)), and orthorhombic at 85 K with a = 10.319(2), b = 10.321(2), c = 10.320(2) Angstrom (space group P2(1)2(1)2(1)), respectively. Precise single-crystal analyses of these phases indicate that Rb2Cd2(SO4)(3) distorts initially from cubic to monoclinic upon cooling followed by a significant reorientation of the SO4 tetrahedra, resulting in an orthorhombic symmetry upon further cooling. The three structures have been established unequivocally using the same crystal. There is no indication of the formation of an intermediate triclinic phase or any lattice disorder as conjectured in several earlier reports on compounds belonging to the type I langbeinite. The bond valence sum analyses of the coordination around the Rb sites indicate asymmetry in the bond strengths which could be the driving force of the ferroelectric behavior in these materials.

Formato

application/pdf

application/pdf

Identificador

http://eprints.iisc.ernet.in/39653/1/Variable_Temperature_X.pdf

http://eprints.iisc.ernet.in/39653/2/Variable_Temperatur.......pdf

Nalini, G and Row, Guru TN (2002) Variable temperature x-ray crystal structure analysis of a type I langbeinite: Rb2Cd2(SO4)(3). In: Chemistry of Materials, 14 (11). pp. 4729-4735.

Publicador

American Chemical Society

Relação

http://pubs.acs.org/doi/abs/10.1021/cm020566h

http://eprints.iisc.ernet.in/39653/

Palavras-Chave #Solid State & Structural Chemistry Unit
Tipo

Journal Article

PeerReviewed