STRUCTURAL AND THERMAL PARAMETERS FOR RUTILE AND ANATASE

被引:710
作者
HOWARD, CJ [1 ]
SABINE, TM [1 ]
DICKSON, F [1 ]
机构
[1] UNIV TECHNOL SYDNEY,BROADWAY,NSW 2007,AUSTRALIA
来源
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE | 1991年 / 47卷
关键词
D O I
10.1107/S010876819100335X
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Neutron powder diffraction patterns from rutile (TiO2, P4(2)/mnm, a = 4.594, c = 2.959 angstrom) and anatase (TiO2, I4(1)/amd, a = 3.785, c = 9.514 angstrom) have been analysed by the Rietveld method. The positional parameters were determined to be x(O) = y(O) = 0.30478 (6) in rutile and z(O) = 0.20806 (5) in anatase. The anisotropic thermal parameters were also determined. The results from this constant-wavelength neutron diffraction study are in remarkably good agreement with the results from a recently published analysis of time-of-flight neutron data from the same phases. A comparison is made with results from earlier X-ray single-crystal investigations of these polymorphs of titania, and again the agreement is good. In particular, there is no evidence for any significant difference between X-ray and neutron determinations of the oxygen position such as might have resulted from polarization effects. The thermal vibrations show marked anisotropy, which appears to be determined by the stereochemistry of the crystal structure. The Debye temperatures estimated from the diffraction data are 600 (10) K for rutile and 520 (10) K for anatase at room temperature.
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页码:462 / 468
页数:7
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