New cation-disordered quaternary selenides Tl2Ga2TtSe6 (Tt=Ge, Sn).

Autor: Babizhetskyy, Volodymyr, Levytskyy, Volodymyr, Smetana, Volodymyr, Wilk-Kozubek, Magdalena, Tsisar, Oksana, Piskach, Lyudmyla, Parasyuk, Oleg, Mudring, Anja-Verena
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Zdroj: Zeitschrift für Naturforschung B: A Journal of Chemical Sciences; Feb2020, Vol. 75 Issue 1/2, p135-142, 8p
Abstrakt: Two new quaternary selenides of the α-TlSe structure type have been synthesized and characterized. Single crystal X-ray diffraction analysis has revealed that Tl2Ga2SnSe6 crystallizes with space group I4/mmc, a = 8.095(1), c = 6.402(1) Å, with a refined composition of Tl1−xGa1−ySnySe2 (x = y = 0.345(5)), Z = 4, R1 = 0.028; wR2 = 0.066. The crystal structure of the isostructural compound Tl2Ga2GeSe6 has been determined by means of powder X-ray diffraction: space group I4/mmc, Z = 4, a = 8.0770(4), c = 6.2572(5) Å, refined composition Tl1−xGa1−yGeySe2, x = 0.343(5), y = 0.35(2), (RB(I) = 0.084; RP = 0.041; RPw = 0.058). According to their optical absorption spectra all compounds are semiconductors with relatively narrow direct band gaps of 2.15(3) and 2.05(5) eV for the Ge and Sn phase, respectively. [ABSTRACT FROM AUTHOR]
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