Dec 212012
Red Kite III - January 2013

The third meeting of the Red Kite network will be held on Thursday 10th January, 2013 in the Main Lecture Theatre in the Physical and Theoretical Chemistry Laboratory, Oxford.  Attendance will be courtesy of the John Fell Oxford University Research Fund.  The meeting will consist of three sessions, each commencing with a half hour … Read the rest

Dec 202012
DetOx: A Program for Determining Anomalous Scattering Factors of Mixed-Oxidation-State Species (K.J. Sutton, S.A. Barnett, K.E. Christensen, H. Nowell, A.L. Thompson, D.R. Allan and R.I. Cooper)

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

Sep 212012
CRYSTALS Enhancements: Asymmetric Restraints (R. I. Cooper, A. Thorn and D. J. Watkin)

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

Aug 102012
Summer Conferences - ACA Annual Meeting 2012, ECM 27 and Aperiodic 2012

Summer is conference season and the members of Chem. Cryst. have been on the road to the ACA in Boston and the ECM in Bergen.  In September, Kirsten will also be attending the 7th International Conference on Aperiodic Crystals, to be hosted in Cairns, Australia.  Contributions include:

David J. Watkin, Richard I. Cooper & … Read the rest

Aug 022012
ACA Student Lecturer Award

Congratulations to Karim Sutton, who has been awarded a Margaret C. Etter Student Lecturer Award at the recent American Crystallographic Association annual meeting in Boston.

He presented his recent research determining oxidation states in mixed-valent materials using tunable synchrotron radiation on Diamond beamline I19.

The awards were established to honour the memory of Professor … Read the rest

Apr 302012
Applications of Leverage Analysis in Structure Refinement (S. Parsons, T. Wagner, O. Presly, P. A. Wood and R. I. Cooper)

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

Apr 202012
BCA Spring Meeting 2012

The 2012 Meeting of the British Crystallographic Association was held at Warwick University.  Oxford was very well represented this year with Kirsten Christensen chairing the Programme Committee and prizes being awarded to Joe Paddison, Nick Funnell and Emma McKinley.

Other contributions from Oxford include:

Karim J. Sutton, Kirsten E. Christensen, Amber L. Thompson & … Read the rest

Mar 192012
Alkyl-chain Disorder in Tetraisohexylammonium Bromide (M. A. Kelland and A. L. Thompson)

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

Feb 192012
An Integrated X-ray and Molecular Dynamics Study of Uranyl-salen Structures and Properties (G. M. Lombardo,  A. L. Thompson,  F. P. Ballistreri,  A. Pappalardo,  G. T. Sfrazzetto,  G. A. Tomaselli,  R. M. Toscano and F. Punzo)

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