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The polymorphic modification of CeRuSnтезисы доклада
- Авторы: Vera Gribanova, Elena Murashova, Yurii Seropegin, Fedor Moiseev, Alexander Gribanov
- Сборник: 18th International Conference on Solid Compounds of Transitional Elements, Lisboa 31st March - 5th April 2012, Book of Abstracts
- Тезисы
- Год издания: 2012
- Место издания: Lisbon University Lisbon, Portugal
- Первая страница: 109
- Последняя страница: 109
- Аннотация: Recently crystal structure and physical properties of the equiatomic ternary compound CeRuSn were reported in [1, 2]. It’s crystal structure was described as a superstructure of the monoclinic CeCoAl type through a doubling of the subcell c axis: C2/m, a=11.561 Å, b=4.759 Å, c=10.233 Å, β=102.89° [1] (phase I). While investigating the Ce-Ru-Sn ternary system in the wide concentration range we confirmed the atomic order of CeRuSn as a superstructure of the monoclinic CeCoAl type and have detected the new polymorphic form, which derived also from parent CeCoAl type through not doubling but tripling the unit cell along the c axis. The equiatomic Ce33.3 Ru33.3 Sn33.4 (at. %) alloy was synthesized from the pure elements by arc-melting in an argon atmosphere and annealed at 720 °C for 30 days. Single crystal of CeRuSn was studied by X-ray diffraction technique: C2/m, a=11.5702(12) Å, b=4.7429(5) Å, c=15.241(2) Å, β = 103.51(1) ° R1 = 0.034 for 1806 F2 and 55 variables (phase II). The main features of that new polymorphic modification are the extremely short Ce-Ru distances for two from three crystallographically independent cerium sites: d(Ce-Ru)1 = 2.267 Å and d(Ce-Ru)2 = 2.429Å, while the third d(Ce-Ru)3 = 2.920 Å is usual value for the interatomic distance between Rare Earth and transitional metal. Both polymorphic modification of CeRuSn were found in the annealed Ce33.3 Ru33.3 Sn33.4 (at.%) alloy by powder diffraction. Rietveld refinement of the powder X-ray pattern revealed 63 % of phase I and 37 % of phase II in the investigated specimen. The crystal chemistry of CeCoAl, CeRuSn(I) and CeRuSn (II) is discussed in the frame of a group-subgroup scheme. DTA measurements revealed the presence of two very close peaks at 1053 and 1058 °C. This work is financially supported by Russian Foundation for Basic Research (RFBR, Grants No. 11-03-00957 and 11-03-01191)
- Добавил в систему: Грибанов Александр Викторович