Can anyone tell me the wyckoff positions of Bi, K, Ti and O in Bi0.5K0.5TiO3 and space group?

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Daniel Lundberg

Hi, Bac!

I found a total of three publications dealing with structures with that formula, two older (cubic) and one newer (tetragonal):

"Physical-chemical investigation of the formation of complex ferroelectrics with perovskite structure" [Agranovskaya, A.I.; Izvestiya Akademii Nauk SSSR, Seriya Fizicheskaya (1960), 24, 1275-1281]

"X-ray determination of the symmetry of the ferroelectric compounds K.5 Bi.5 Ti O3 and Na.5 Bi.5Ti O3 and the high-temperature phase transition in K.5 Bi.5 Ti O3 [Ivanova, V.V. et al. Izvestiya Akademii Nauk SSSR, Seriya Fizicheskaya, (1962), 26, 358-360]

"A structural study of the (Na1-x Kx)0.5 Bi0.5 Ti O3 perovskite series as a function of substitution (x) and temperature" [Jones, G.O. et al. Powder Diffraction, (2002), 17(4), 301-319]

Crystal details for the three studies, sorted by year, can be found in the attached file, but I would check out the original references just in case.

Regards,

Daniel

Gert Nolze

Please note that the tetragonal phase given by Daniel is a subgroup of the cubic phase, caused by a tiny shift of the oxygen arrangement which cause a) a symmetry change, and b) a small deformation of the crystal lattice. The first forces to describe the structure as tetragonal lattice, which might affect the lattice as well but don't have to. Here it does...