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  • 1 Romanian Academy Timisoara Branch Bd. M.Viteazul 24 Timisoara RO1900 Romania Timisoara Branch Bd. M.Viteazul 24 Timisoara RO1900 Romania
  • | 2 Tehnical University P-ta Victoriei 2 Timisoara RO1900 Romania Timisoara RO1900 Romania
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Abstract  

The aim of this study is to investigate the influence of some monovalent counter-ions (NH4+, K+ and Cs+) on thermal behavior of polyoxometalates derived from H3PMo12O40 (HPM) and H4PVMo11O40 (HPVM) by replacing the protons. The IR and UV-VIS-DRS spectra of some acid and neutral NH4+, K+, Cs+ salts, which derived from HPM and HPVM, confirmed the preservation of Keggin units (KU) structure. The X-ray diffraction spectra clearly showed the presence of a cubic structure. The non-isothermal decomposition of studied polyoxometalates proceeds by a series of processes: the loss of crystallization water; the loss of O2 accompanying with a reduction of V5+→V4+ and Mo6+→Mo5+; the loss of constitution water started at 360C for HPVM salts and 420C for HPM salts; the decomposition of ammonium ion over 420C with NH3, N2 and H2O elimination and simultaneous processes of reduction (V5+→ V4+ and Mo6+→ Mo5+ or Mo4+) associating with endothermic effects; reoxidation of Mo5+, Mo4+ and V4+with a strong exothermic effect; destruction of KU to the oxides: P2O5, MoO3 and V2O5 and the crystallization of MoO3.

Manuscript Submission: HERE

  • Impact Factor (2019): 2.731
  • Scimago Journal Rank (2019): 0.415
  • SJR Hirsch-Index (2019): 87
  • SJR Quartile Score (2019): Q3 Condensed Matter Physics
  • SJR Quartile Score (2019): Q3 Physical and Theoretical Chemistry
  • Impact Factor (2018): 2.471
  • Scimago Journal Rank (2018): 0.634
  • SJR Hirsch-Index (2018): 78
  • SJR Quartile Score (2018): Q2 Condensed Matter Physics
  • SJR Quartile Score (2018): Q2 Physical and Theoretical Chemistry

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Journal of Thermal Analysis and Calorimetry
Language English
Size A4
Year of
Foundation
1969
Volumes
per Year
4
Issues
per Year
24
Founder Akadémiai Kiadó
Founder's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
Publisher Akadémiai Kiadó
Springer Nature Switzerland AG
Publisher's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
CH-6330 Cham, Switzerland Gewerbestrasse 11.
Responsible
Publisher
Chief Executive Officer, Akadémiai Kiadó
ISSN 1388-6150 (Print)
ISSN 1588-2926 (Online)

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