Solving Crystal Structures from Powder Data. IV. The Use of the Patterson Information for Estimating the |F|'s

Abstract

The positivity of the Patterson function is used as prior information for the decomposition of a powder diffraction pattern. An automatic procedure is described which, integrated with the Le Bail method, is able to provide estimates of IFI values that are often remarkably better than those obtained by application of standard techniques. The procedure, implemented in a computer program, has been applied to a set of test structures (experimental data); the results show that, particularly for structures with some heavy atoms, the new estimates of the structure-factor moduli are far better (on average) than those obtained via the default application of EXTRA [Altomare et al. (1995). J. Appl. Cryst. 28,[842][843][844][845][846].

Cavity‐Shaped Ligands: Calix[4]arene‐Based Monophosphanes for Fast Suzuki–Miyaura Cross‐Coupling

“…5-Diphenylphosphanyl-25,26,27,28-tetrahexyloxy-calix [4]arene (6) SIR-97, [37] which revealed the non-hydrogen atoms of the molecule. After anisotropic refinement, many hydrogen atoms were found with a Fourier difference analysis.…”

“…After anisotropic refinement, many hydrogen atoms were found with a Fourier difference analysis. The whole structure was refined with SHELX-97 [38] and full-matrix least-square techniques (use of The structure was solved with SIR-97, [37] which revealed the non-hydrogen atoms of the molecule. After anisotropic refinement, many hydrogen atoms were found with a Fourier difference analysis.…”

EXPO: a program for full powder pattern decomposition and crystal structure solution

“…(iv) the positivity of the Patterson function (Altomare, Foadi et al, 1998); (v) the availability of a partial structure .…”

High‐Pressure Investigations under CO/H2 of Rhodium Complexes Containing Hemispherical Diphosphites

“…; FA C H T U N G T R E N N U N G (000) = 3984; T = 120 K. Diffraction data were collected by using a NONIUS Kappa CCD diffractometer (graphite Mo Ka radiation, l = 0.71073 ). The structure was solved by using SIR-97, [41] which revealed the non-hydrogen atoms of the molecule. The structure was refined with SHELXL97 [42] using a riding model for hydrogen atoms; 2437 variables and 37181 observations with I > 2.0s(I).…”