LOW SYMMETRY AND SYMMETRY CHANGES IN THE THORTVEITITE STRUCTURE

摘要

The non-centrosymmetric structure of ScFeGe_2O_7 was investigated by X-ray powder diffraction measurements by Rietveld refinement performed in the GS AS and EXPGUI software. The sample presents a triclinic symmetry with a space group P1 (No. 1), a = 5.3434(8), b = 5.3145(8), c = 4.8732 (7) A, a =99.468(2), p= 97.257(2), 7=104.609(2)°, V= 130.03(5) A~3, Z= 1; wRp = 0.047, Rp = 0.04, and reduced X~2 was 2.176 for 64 variables.