Registration Number
0223U003938,
0119U100025
, R & D reports
Title
Polyoxometalates, orthovanadates and oxyorthosilicates of transition metals and lanthanides for creation of new materials
popup.stage_title
Head
Rozantsev Georgiy M., Доктор хімічних наук
Registration Date
27-07-2023
Organization
Vasyl' Stus Donetsk National University
popup.description2
The results of X-ray structural analysis of single crystals of isostructural Na9[Ln(W5O18)2]·nH2O normal salts with heteropoly tungstate anion with Peacock–Weakley structure are systematized. By establishing the structural parameters in a series of isostructural normal salts Na9[Ln(W5O18)2]·35H2O (Ln is a lanthanide heteroatom), a linear decrease in the length of the Ln—Ob(W) bond and interatomic distances О...О in the {LnO8} polyhedron in the heteropoly anion with the Peacock–Weakley structure of the Ln(III)–heteroatom was established. The interaction in an aqueous solution of WO42– containing Mn2+ and acidifications up to Z=1.00 was investigated using the pH-potentiometric titration method, followed by mathematical modeling using the CLINP 2.1 program. An equilibrium model was selected, which includes ion pairs [MnOH+, W12O40(ОН)2]9–; [Mn2+, W12O40(ОН)2]8–; [Mn2+, HW12O40(ОН)2]7–; [Mn2+, H2W12O40(ОН)2]6–; [Mn2+, H3W12O40(ОН)2]5–. The values of the logarithms of the ion pair formation concentration constants calculated for the model were the basis for calculating the logarithms of the thermodynamic constants using the Pitzer method. Within the framework of V.S.Urusov's crystal energetic theory of isomorphic substitutions, the energy of mixing (interaction of parameters) was calculated in the systems (Lu1–xLnx)[(SiO4)0.5O0.5], where Ln are rare earth elements (REEs) of the La–Yb series, and (Sc1–xLnx)[(SiO4)0.5O0.5], where Ln is REEs of the Tb–Lu and Y series. The dependence of the decomposition temperature of solid solutions on the REEs number and, respectively, (x) was obtained, using which a diagram of the thermodynamic stability of solid solutions was constructed, which also allows predicting the substitution limits depending on the temperature or the decomposition temperature at the specified substitution limits. The results of the work can be useful when choosing the composition of components in matrices and the amount of activator (dopant) in new materials.
Product Description
popup.authors
Baumer Vyacheslav M.
Get'man Yevgen Ivanovych
Duvanova Ella S.
Knyzhnyk Ivan A.
Kordysh Oleksii M.
Mariichak Oleksandra Yu.
Oleksii Yuliia A.
Popova Alina Volodymyrivna
Radio Serhii V.
popup.nrat_date
2023-07-27
