Author(s):
1. Ubavka Mioč, Fakultet za fizičku hemiju, Serbia
2. Milorad Davidović, Institut Goša, Milana Rakića 35, Beograd, Serbia
3. Pavle Tančić, Geološki zavod Srbije, Serbia
4. Svjetlana Sredić, Rudarski fakultet Prijedor, Republic of Srpska, Bosnia and Herzegovina
5. Zoran Nedić, Fakultet za fizičku hemiju, Serbia

Abstract:
Abstract: In this paper phase transformations of acidic copper salts of 12-tungstophosphoric acid were studed using the thermogravimetric (TGA) and differential thermal analysis (DTA) technique at a temperature interval from room temperature to 800 °C. The structural phase transformations were followed through characteristic bands for the host lattice in the infrared spectra, as well as of X-ray powder diffraction analysis (XRPD). From room temperature to 205 °C Cu(II) salt of 12-tungstophosphoric acid goes through the dehydration process, which characterizes the formation of different crystallohydrates. This suggests that all of these phase transformations are related to the change in the local structure of the heteropoly acid salt, i.e. to the secondary structure of Kegginʼs anion. The exothermic peak corresponds to the process of solid-solid recrystallization and the formation of new copper doped phosphate tungsten bronze. These structural changes are clearly expressed in infrared spectra and X-ray diffraction measurements, which indicates the change of the primary structure of Keggin's anion.

Key words:
Keywords: CuHPW12O40 × 25H2O, phase transformations, bronze.

Thematic field:
SYMPOSIUM A - Science of matter, condensed matter and physics of solid states

Date of abstract submission:
24.07.2018.

Conference:
Contemporary Materials 2018 - Savremeni Materijali

Applied paper from author