research papers
The electron density and atomic displacements in the perovskite SrTiO3 have been studied using extensive and accurate γ-ray diffraction data (λ = 0.0392 Å) at room temperature. The six strongest low-order structure factors have been determined under extinction-free conditions. Gram–Charlier series expansion of the thermal parameters have revealed no evidence for anharmonicity. The population of the 3d subshell on Ti is found to be close to zero, in agreement with the observed magnetic behaviour. The electronic properties at the bond critical points indicate ionic Ti—O and Sr—O interactions of different strengths, which is corroborated by the net charges of the atomic basins [q(Sr) = 1.18 |e|, q(Ti) = 3.10 |e|, q(O) = −1.42 |e|]. A critical comparison is made with earlier experimental results from laboratory X-ray, synchrotron X-ray, electron and neutron diffraction studies. Agreement and discrepancies are identified and resolved.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108767305013231/sh5025sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108767305013231/sh5025sup2.hkl |
Computing details top
Data reduction: xtal_ADDREF_SORTRF; program(s) used to solve structure: Xtal; program(s) used to refine structure: Xtal; molecular graphics: Xtal; software used to prepare material for publication: xtal_CIFIO.
(I) top
Crystal data top
SrTiO3 | V = 59.56 Å3 |
Cubic, p_m_3_m | Dx = 5.116 Mg m−3 |
Hall symbol: -p_4_2_3 | Gamma-radiation (316.5 KeV) |
a = 3.9053 Å | T = 293 K |
Data collection top
776 measured reflections | θmax = 3.9°, θmin = 0.3° |
174 independent reflections | h = 0→12 |
174 reflections with refl_observed_if_F2_ > _.000_σ(F2) | k = −8→12 |
Rint = 0.012 | l = −2→8 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
ti | 0.50000 | 0.50000 | 0.50000 | 0.00395* | |
sr | 0.00000 | 0.00000 | 0.00000 | 0.00578* | |
o | 0.50000 | 0.50000 | 0.00000 | 0.00732 |
Atomic displacement parameters (Å2) top
U11 | U22 | U33 | U12 | U13 | U23 | |
o | 0.00932 | 0.00932 | 0.00333 | 0.00000 | 0.00000 | 0.00000 |