Revised Bismuth Chloroselenite System: Evidence of
a Noncentrosymmmetric Structure with a Giant Unit Cell
Almaz Aliev
V. M. Kovrugin
Marie Colmont
Christine Terryn
Marielle Huvé
O. I. Siidra
S. V. Krivovichev
Olivier Mentré
10.1021/cg500293w.s001
https://acs.figshare.com/articles/journal_contribution/Revised_Bismuth_Chloroselenite_System_Evidence_of_a_Noncentrosymmmetric_Structure_with_a_Giant_Unit_Cell/2286529
The
reactions between PbO, Bi<sub>2</sub>O<sub>3</sub> (or BiOCl),
and SeO<sub>2</sub> by the chemical vapor transport method using HCl
as a transporting agent afforded three novel bismuth/lead chloroselenites,
namely, β-BiSeO<sub>3</sub>Cl (<b>1</b>), Bi<sub>6</sub>(SeO<sub>3</sub>)<sub>4</sub>Cl<sub>10</sub> (<b>2</b>), and
PbBi<sub>10</sub>(SeO<sub>3</sub>)<sub>12</sub>Cl<sub>8</sub> (<b>3</b>). Compound <b>1</b> is noncentrosymmetric (space group <i>Cc</i>, SHG active) and has a giant unit cell (<i>V</i> = 19792(2) Å<sup>3</sup>). In the context of the complex BiSeO<sub>3</sub>Cl phase diagram reported by Oppermann et al., it was assigned
to the undescribed β-form on the basis of its IR spectra and
powder X-ray diffraction pattern. The comparison between the α-,
β-, and γ-forms suggests their formation via the condensation
of volatile Bi(SeO<sub>3</sub>)Cl molecules. Analysis of the structures
of the α-, β-, and γ-forms indicates that the α
→ β → γ phase transitions are associated
with a dramatic fluctuation of structural complexity together with
the transitional character of the β phase. Compounds <b>1</b> and <b>3</b> are layered compounds with identical ([M<sub>8</sub>Cl<sub>16</sub>]<sup>8+</sup> and [M<sub>14</sub>(SeO<sub>3</sub>)<sub>24</sub>]<sup>6−</sup>) layers, where M stands
for Bi in <b>1</b> and Pb/Bi in <b>3</b>. There are additional
[Bi<sub>12</sub>Cl<sub>32</sub>]<sup>4+</sup> layered subunits in <b>1</b>. The crystal structure of <b>2</b> consists of the
[Bi<sub>6</sub>(SeO<sub>3</sub>)<sub>4</sub>Cl<sub>10</sub>] building
blocks forming an open framework with six-membered-ring channels.
These three compounds complete the poorly known bismuth selenium oxochloride
panorama.
2014-06-04 00:00:00
bismuth selenium oxochloride panorama
Bi 2O
Compounds 1
IR spectra
Noncentrosymmmetric Structure
SHG
SeO 2
Giant Unit CellThe reactions
crystal structure
chemical vapor transport method
Revised Bismuth Chloroselenite System
space group Cc
Bi 12Cl
BiSeO 3Cl phase diagram
giant unit cell
β phase