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Title: Structures and phases transition in hexylenediammonium pentachlorobismuthate (III) [NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}]BiCl{sub 5} crystal

Journal Article · · Journal of Solid State Chemistry
;  [1];  [2]
  1. Equipe de Physico-Chimie des Matériaux Inorganiques, Université Ibn Tofail, Faculté des Sciences, B. P. 133, Kenitra 14000 (Morocco)
  2. Unité de Catalyse et de Chimie du Solide, CNRS UMR 8181 (Equipe de Chimie du Solide), ENSCL, USTL, VILLENEUVE D'ASCQ Cedex 59655 (France)

The crystal structure of [NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}]BiCl{sub 5} was determined at: 223 K [P2{sub 1}2{sub 1}2{sub 1} (Z=4), a=7.788(1), b=13.886(2), c=13.972(2) Å], 308 K [P2{sub 1}/n (Z=8), a=19.972(3), b=7.772(2), c=20.166(3) Å, β=92.32(1)°] and 378 K [Pnma (Z=4), a=13911(2), b=7.834(7), c=14.457(2) Å]. It was consisted of isolated (BiCl{sub 5}{sup 2−}){sub n} anionic chains composed by distorted octahedra BiCl{sub 6}{sup 3−} sharing two corners and {sup +}NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}{sup +} cations placed in the free cavities between anionic chains. In the β phase, there are two crystallographically inequivalent cations and two one-dimensional anionic chains (BiCl{sub 5}{sup 2−}){sub n} in which BiCl{sub 6}{sup 3−} octahedra was doubly tilted and simply tilted. Two structural phase transitions at low and high temperatures α (P2{sub 1}2{sub 1}2{sub 1}, 223 K)↔β (P2{sub 1}/n, 308 K)↔γ (Pnma, 373 K) are observed and discussed. It was crystallographically showed that both anionic and cationic entities contribute to phase transitions mechanisms. The BiCl{sub 6}{sup 3−} octahedra were found to posses significant distortions on decreasing temperature and became more distorted in α (223 K) phase. It is argued that these deformations are caused by weak to moderate N--H···Cl hydrogen bonding. - Graphical abstract: Projection of the crystal structure of [NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}]BiCl{sub 5} down the a axis at 208 K. Highlights: ► The crystal shows two phase transitions: α(223 K)↔β(308 K)↔γ(373 K). ► A discontinuous transition may be occurred between α and β phases. ► The α↔β and β↔γ phase transitions are of first order. ► Both anionic and cationic motions contribute to phase transition mechanisms. ► The BiCl{sub 6}{sup 3−} octahedra showed significant distortions on decreasing temperature.

OSTI ID:
22304527
Journal Information:
Journal of Solid State Chemistry, Vol. 200; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
Country of Publication:
United States
Language:
English