TY - JOUR

T1 - Order-disorder transition and thermal behavior of paracelsian-type MGa2Ge2O8 (M = Sr, Ba) compounds

AU - Горелова, Людмила Александровна

AU - Юхно, Валентина Анатольевна

AU - Кржижановская, Мария Георгиевна

AU - Верещагин, Олег Сергеевич

PY - 2024/1/1

Y1 - 2024/1/1

N2 - Two Ga–Ge disordered feldspar-related compounds MGa2Ge2O8 (M = Sr, Ba) with paracelsian topology were synthesized for the first time using the melt crystallization methods (1300–1400 °C) and rapid cooling. Their stability was studied under high-temperature conditions using in situ single-crystal (up to 1000 °C) and powder (up to 1050 °C) X-ray diffraction. Both compounds are stable in the studied temperature range. The refinement of the crystal structure of BaGa2Ge2O8 at different temperatures does not demonstrate any ordering processes. The thermal expansion of both compounds has anisotropic character (αmax/αmin = 3.7 and 3.9 for SrGa2Ge2O8 and BaGa2Ge2O8, respectively), wherein the maximum and minimum expansion is observed within the bc plane. The anisotropy degree of MGa2Ge2O8 increases as the size of extraframework cation increasing. Simultaneously this process leads to the decreasing of MGa2Ge2O8 stability range. The influence of the crystallization procedure on order-disorder process of MGa2Ge2O8 is discussed.

AB - Two Ga–Ge disordered feldspar-related compounds MGa2Ge2O8 (M = Sr, Ba) with paracelsian topology were synthesized for the first time using the melt crystallization methods (1300–1400 °C) and rapid cooling. Their stability was studied under high-temperature conditions using in situ single-crystal (up to 1000 °C) and powder (up to 1050 °C) X-ray diffraction. Both compounds are stable in the studied temperature range. The refinement of the crystal structure of BaGa2Ge2O8 at different temperatures does not demonstrate any ordering processes. The thermal expansion of both compounds has anisotropic character (αmax/αmin = 3.7 and 3.9 for SrGa2Ge2O8 and BaGa2Ge2O8, respectively), wherein the maximum and minimum expansion is observed within the bc plane. The anisotropy degree of MGa2Ge2O8 increases as the size of extraframework cation increasing. Simultaneously this process leads to the decreasing of MGa2Ge2O8 stability range. The influence of the crystallization procedure on order-disorder process of MGa2Ge2O8 is discussed.

KW - SrGa2Ge2B2O8

KW - BaGa2Ge2B2O8

KW - Feldspar

KW - Paracelsian

KW - High-temperature

KW - Order-disorder

KW - BaGa2Ge2B2O8

KW - Feldspar

KW - High-temperature

KW - Order-disorder

KW - Paracelsian

KW - SrGa2Ge2B2O8

UR - https://www.mendeley.com/catalogue/a54f88c1-2398-3045-89c7-7c4b883e1a36/

U2 - 10.1016/j.jssc.2023.124429

DO - 10.1016/j.jssc.2023.124429

M3 - Article

VL - 329

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

SN - 0022-4596

M1 - 124429

ER -