TY - JOUR

T1 - Comparative characteristics of Bi- and La- doped (Ca/Sr)MoO4-based materials with a defect scheelite-type structure

AU - Mikhaylovskaya, Zoya

AU - Klimova, Alexandra

AU - Petrova, Sofia

AU - Pankrushina, Elizaveta

AU - Buyanova, Elena

N1 - Текст о финансировании #1 This work was fulfilled as part of the Government task to the Institute of Geology and Geochemistry (theme No. AAAA-A19-119071090011-6). The retrofit and development of the Geoanalitik Shared Facilities Center of the Institute of Geology and Geochemistry is carried out under a grant from the Ministry of Higher Education and Science of the Russian Federation (agreement No. 075-15-2021-680). Текст о финансировании #2 This work was fulfilled as part of the Government task to the Institute of Geology and Geochemistry (theme No. AAAA-A19-119071090011-6). The retrofit and development of the Geoanalitik Shared Facilities Center of the Institute of Geology and Geochemistry is carried out under a grant from the Ministry of Higher Education and Science of the Russian Federation (agreement No. 075-15-2021-680). The XRD data were obtained in Ural-M center of Institute for Metallurgy, Ural Branch of RAS, the Raman data were obtained in Geoanalytic center of Zavaritsky Institute of Geology and Geochemistry, Ural Branch of RAS.

PY - 2023

Y1 - 2023

N2 - CaMoO4- and SrMoO4-based scheelite-type phases are noteworthy functional materials, whose properties strongly correlate with their structure. This work is devoted to La- or Bi-doped scheelite-type molybdates. The purpose of the present study is to quantify the effect of isolated electron pairs of bismuth on the distortion of the structure and related properties. Conventional solid-state technology was used for the synthesis of (Ca/Sr)1–3xLa2xФxMoO4 and Sr1–3xBi2xФxMoO4, (0.025≤ x ≤ 0.275). The structure was investigated by X-ray powder diffraction and Raman spectroscopy. Rates of structure distortion were characterised by the analysis of the autocorrelation function (AAF) of Raman spectra. Energy gaps were calculated by the Kubelka-Munk method. The conductivity was studied with a.c. impedance spectroscopy. For (Ca/Sr)1−3x(Bi/La)2xФxMoO4 series 0.025 ≤ x ≤ 0.15 compositions show a basic defect scheelite structure, while 0.15 < x ≤ 0.225 compositions of Bi-doped samples exhibit tetragonal supercells. The chemical compression of unit cell is more evident in the case of Bi-doping, indicating the preferred orientation of the isolated electron pairs. The distortion of MoO4 polyhedra showed by AAF was more significant for Sr1−3xBi2xФxMoO4 than for Sr1−3xLa2xФxMoO4, the Δcorr parameters for Bi-doped compositions were almost double in comparison with La-doped one in the range of 50–600 cm–1 of the Raman shift. The «critical» x = 0.15 point was also clearly indicated by Δcorr parameter. The AAF of the Raman spectra of solid oxides was shown to be a good tool for prediction of properties and points of phase transitions in solid oxides. Copyright © 2024 by Animal Bioscience.

AB - CaMoO4- and SrMoO4-based scheelite-type phases are noteworthy functional materials, whose properties strongly correlate with their structure. This work is devoted to La- or Bi-doped scheelite-type molybdates. The purpose of the present study is to quantify the effect of isolated electron pairs of bismuth on the distortion of the structure and related properties. Conventional solid-state technology was used for the synthesis of (Ca/Sr)1–3xLa2xФxMoO4 and Sr1–3xBi2xФxMoO4, (0.025≤ x ≤ 0.275). The structure was investigated by X-ray powder diffraction and Raman spectroscopy. Rates of structure distortion were characterised by the analysis of the autocorrelation function (AAF) of Raman spectra. Energy gaps were calculated by the Kubelka-Munk method. The conductivity was studied with a.c. impedance spectroscopy. For (Ca/Sr)1−3x(Bi/La)2xФxMoO4 series 0.025 ≤ x ≤ 0.15 compositions show a basic defect scheelite structure, while 0.15 < x ≤ 0.225 compositions of Bi-doped samples exhibit tetragonal supercells. The chemical compression of unit cell is more evident in the case of Bi-doping, indicating the preferred orientation of the isolated electron pairs. The distortion of MoO4 polyhedra showed by AAF was more significant for Sr1−3xBi2xФxMoO4 than for Sr1−3xLa2xФxMoO4, the Δcorr parameters for Bi-doped compositions were almost double in comparison with La-doped one in the range of 50–600 cm–1 of the Raman shift. The «critical» x = 0.15 point was also clearly indicated by Δcorr parameter. The AAF of the Raman spectra of solid oxides was shown to be a good tool for prediction of properties and points of phase transitions in solid oxides. Copyright © 2024 by Animal Bioscience.

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=85180602779

UR - https://elibrary.ru/item.asp?id=60040553

U2 - 10.15826/chimtech.2023.10.4.11

DO - 10.15826/chimtech.2023.10.4.11

M3 - Article

VL - 10

JO - Chimica Techno Acta

JF - Chimica Techno Acta

SN - 2409-5613

IS - 4

M1 - 202310411

ER -