Dibarium lead(IV) tetraoxide, Mr = 545·88, tetragonal, I4/mmm, Z = 2.T=5K: a = 4·29650 (2), c= 13·2285 (1)Å, V= 244·196 (4) Å3, Dx = 7·424 g cm -3. T=298K: a = 4·30241 (1), c = 13·26070 (5) Å, V= 245·466 (2) Å3, Dx = 7·386 g cm-3. Rietveld refinement using time-of-flight powder neutron diffraction data [TOF 30000·103000 μs, 184 contributing reflections, 5 K; TOF 35000·110000 μs, 122 contributing reflections, 298 K] resulted in Rwp = 2·6 (Rexp = 2·1), Χ2 = 1·5 at 5K and Rwp = 5·1 (R exp = 3·0), Χ2 = 3·0 at 298 K. Our results confirm the room-temperature structure determined earlier by X-ray work and show the lack of structural distortions down to 5 K. They also permit a very precise determination of the geometry of the Pb06 octahedra, showing that the tetragonal distortion had been overestimated before by at least a factor of 10. The implication of this result for recent band-structure calculations is stressed.
|ジャーナル||Acta Crystallographica Section C: Crystal Structure Communications|
|出版ステータス||Published - 1991 12月 1|
ASJC Scopus subject areas