J. Sync. Rad (2013). 20, 200–204. [ doi:10.1107/S0909049512044007 ]
Overlapping absorption edges will occur when an element is present in multiple oxidation states within a material. DetOx is a program for partitioning overlapping X-ray absorption spectra into contributions from individual atomic species and computing the dependence of the anomalous scattering factors on X-ray energy. … Read the rest
J. Appl. Cryst. (2012). 45, 1057–1060. [ doi:10.1107/S0021889812035790 ]
The traditional Waser distance restraint, the rigid-bond restraint and atomic displacement parameter (ADP) similarity restraints have an equal influence on both atoms involved in the restraint. This may be inappropriate in cases where it can reasonably be expected that the precision of the determination of … Read the rest
J Appl. Cryst. (2012), 45, 417-429. [ doi:10.1107/S0021889812015191 ]
Leverages measure the influence that observations (intensity data and restraints) have on the fit obtained in crystal structure refinement. Further analysis enables the influence that observations have on specific parameters to be measured. The results of leverage analyses are discussed in the context of the … Read the rest
Acta Cryst. (2012), C68, o152-o155. [ doi:10.1107/S0108270112009377 ]
Tetraisohexylammonium bromide [systematic name: tetrakis(4-methylpentyl)azanium bromide], C24H52N+·Br-, is a powerful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space group P3221, contains one ammonium cation and one bromide anion in the asymmetric unit, … Read the rest
Dalton Trans. (2012), 41, 1951-1960. [ doi:10.1039/C1DT11758K ]
Uranium complexes of bis(p-tert-butyl-salicylidene)-1,2-diphenylethylenediamine (1) and bis(salicylidene)-1,2-diphenylethylenediamine (2) have been synthesized and investigated by X-ray single crystal diffraction and MD calculations in Periodic Boundary Conditions. Both compounds form crystals which are densely packed and do not provide voids accessible to … Read the rest
Acta Cryst. (2012), E68, o593-o594. [ doi:10.1107/S1600536812003303 ]
The title compound, C7H13NO3, adopts an approximately planar conformation. The torsion angles in the aliphatic chain between the carbonyl group C atoms range from 172.97 (14) to 179.38 (14)° and the r.m.s. deviation of all non-H atoms is 0.059 Å. … Read the rest
J. Appl. Cryst. (2011), 44, 1017-1022. [ doi:10.1107/S0021889811034066 ]
A summary of the features for investigating absolute structure available in the crystallographic refinement program CRYSTALS is presented, together with the results of analyses of 150 light-atom structures collected with molybdenum radiation carried out with these tools. The results confirm that the Flack and Hooft … Read the rest
CrystEngComm (2011), 13(8) 2923-2929. [ doi:10.1039/c0ce00709a ]
A series of racemic or stereochemically labile chiral borate anions based on the 2,20-biphenol motif was
investigated. All borates were homochiral in the solid state, although in some cases the heterochiral
diastereomers were computed to be thermodynamically preferred (DFT). The crystallographic
preference for the homochiral diastereomer was … Read the rest
Acta Cryst. (2011), A67, 21-34. [ doi:10.1107/S010876731004287X ]
The practical use of the average and difference intensities of Friedel opposites at different stages of structure analysis has been investigated. It is shown how these values may be properly and practically used at the stage of space-group determination. At the stage of least-squares refinement, … Read the rest
J. Appl. Cryst. (2011), 44, 52-59. [ doi:10.1107/S0021889810042470 ]
One of the requirements for the next generation of small-molecule crystallographers is a mathematical programming infrastructure. It should provide a modelling design process, where the model formulation is kept separate from the optimization process to provide gains in reliability, scalability and extensibility, enabling the application … Read the rest