Determination of the correct composition of "Hydrous Lead(II) Oxotellurate(IV)" as PbTeO₃, crystallizing as a new polymorph

Author(s)

Matthias Weil, Mahdi Shirkhanlou, Ekkehard Füglein, Eugen Libowitzky

Abstract

In previous studies, it has been reported that the crystalline product precipitated from the reaction of aqueous solutions of lead(II) salts with sodium oxotellurate(IV) is hydrous lead(II) oxotellurate(IV); however, there have been conflicting specifications of the water content, and the crystal structure of the product is yet undetermined. During the present study, it was shown that the precipitated material does not contain any structural water and in fact represents the third modification (denoted as g-) of PbTeO3, as revealed by thermal analysis, vibrational spectroscopy, single crystal and powder X-ray diffraction. This modification crystallizes in the space group P1 with five formula units in the asymmetric unit, comprising off-centred coordination polyhedra around the PbII cations (coordination numbers: 5-7 with Pb-O distances ranging from 2.3-3.0 Å), and trigonal-pyramidal TeO3 2?? units. The thermal behaviour and structural phase transitions of PbTeO3 were investigated by means of temperature-dependent X-ray powder diffraction and complementary thermal analysis measurements. In addition, the crystal structure of b-PbTeO3 was redetermined, and a comparison was made between the three known polymorphs of PbTeO3.

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

Technische Universität Wien, Netzsch-Gerätebau GmbH.

Journal

Crystals - Open Access Crystallography Journal

Volume

8

No. of pages

15

ISSN

2073-4352

DOI

https://doi.org/10.3390/cryst8010051

Publication date

01-2018

Peer reviewed

Yes

Austrian Fields of Science 2012

104026 Spectroscopy, 105113 Crystallography

Keywords

ASJC Scopus subject areas

Condensed Matter Physics, General Chemical Engineering, General Materials Science, Inorganic Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/c3649dbd-33cf-4f3d-b262-e8b2da95aa94