New Samarium Oxotellurites: Synthesis and Characteristic

Abstract

We synthesized samarium oxotellurites SmMTeO_4.5 (M — Mg, Ba) by the method of ceramic technology with solid-phase interaction (800–1200 °С) of Sm₂O₃ and TeO₂ oxides with MgCO₃ and BaCO₃ carbonates. The compounds were characterized by X-ray and electrophysics methods. It has been established that the synthesized compounds crystallize in the tetragonal syngony with the following crystallographic characteristics: SmMgTeO_4.5 — a = 12.226; c = 5.783 Å, V⁰_un.cell = 864.38 ų, Z = 4, ρ_xray. = 2.876, ρ_pycn. = (2.874±0.002) g∙cm^-3; SmBaTeO_4.5 — a = 12.717; с = 6.132Å, V⁰_un.cell = 991.62ų, Z = 4, ρ_xray. = 3.264, ρ_pycn. = (3.260±0.004) g∙cm^-3; for both tellurites α = β = γ = 90°. The experimental and calculated values of 2 Th and d-sp, X-ray and pycnometric densities, as well as theoretical and experimental values of unit cell volumes are agreed satisfactorily. Thus, we can confirm correctness and reliability of the results of indexing X-ray patterns of new samarium oxotellurites. We found that increase in the ionic radii from Mg to Ba increases the lattice parameters of the synthesized oxotellurites. Oxotellurites are crystallized in the structural types of distorted perovskite P_m3_m. Based on the given study samarium oxotellurites can have semiconductor and ferroelectric properties.