Modulated structure and phase transitions of Sr10Ga6O19.
作者： Hannes Krüger , Biljana Lazić , Erik Arroyabe , Volker Kahlenberg
DOI: 10.1107/S0108768109026974
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摘要: The crystal structure of Sr10Ga6O19 was investigated by in situ single-crystal X-ray diffraction the temperature range 298–673 K. At ambient conditions compound shows a (3 + 1)-dimensional modulated superspace group C2/c(0β0)s0 [a = 34.9145 (13), b 7.9369 (2), c 15.9150 (7) A and β 103.551 (3)°] with modulation wavevector q 0.4288 (2)b*. Whereas presented structural model uses first-order harmonic functions only, some features modulations are discussed utilizing an electron density derived maximum entropy method. Furthermore, two phase transitions were identified: between 453 503 K incommensurate superstructure is replaced doubling lattice constants, 503 673 K basic cell formed, identical to α-Sr10Ga6O19. Under cooling crystals showing combined pattern both superstructures can be obtained. relation these results α-Sr10Ga6O19 [Kahlenberg (2001). J. Solid State Chem. 160, 421–429] discussed.
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