A while ago, I explored how the 3-coordinate halogen compound ClF3 is conventionally analyzed using VSEPR (valence shell electron pair repulsion theory). Here I (belatedly) look at other such tri-coordinate halogen compounds using known structures gleaned from the crystal structure database (CSD).
Archive for the ‘crystal_structure_mining’ Category
A wider look at chlorine trifluoride: crystal structures and data mining.
Friday, June 10th, 2016The geometries of 5-coordinate compounds of group 14 elements.
Monday, May 30th, 2016This is a follow-up to one aspect of the previous two posts dealing with nucleophilic substitution reactions at silicon. Here I look at the geometries of 5-coordinate compounds containing as a central atom 4A = Si, Ge, Sn, Pb and of the specific formula C34AO2 with a trigonal bipyramidal geometry. This search arose because of a casual comment I made in the earlier post regarding possible cooperative effects between the two axial ligands (the ones with an angle of ~180 degrees subtended at silicon). Perhaps the geometries might expand upon this comment?
Bond stretch isomerism. Did this idea first surface 100 years ago?
Tuesday, February 9th, 2016The phenomenon of bond stretch isomerism, two isomers of a compound differing predominantly in just one bond length, is one of those chemical concepts that wax and occasionally wane.[1] Here I explore such isomerism for the elements Ge, Sn and Pb.
References
- J.A. Labinger, "Bond-stretch isomerism: a case study of a quiet controversy", Comptes Rendus. Chimie, vol. 5, pp. 235-244, 2002. https://doi.org/10.1016/s1631-0748(02)01380-2
Could anyone comment on any recent calculated results on the planarity, or lack thereof, of azobenzene?
Sunday, December 20th, 2015Deviations from planarity of trigonal carbon and from linearity of digonal carbon.
Sunday, September 13th, 2015Previously, I explored deviation from ideal tetrahedral arrangements of four carbon ligands around a central (sp3) carbon using crystal structures. Now it is the turn of digonal (sp1) and trigonal (sp2) carbons.
π-Resonance in thioamides: a crystallographic “diff” with amides.
Saturday, September 5th, 2015The previous post explored the structural features of amides. Here I compare the analysis with that for the closely related thioamides.