Simultaneous analysis of changes in long-range and short-range structural order at the displacive phase transition in quartz
Journal of Physics Condensed Matter IOP Publishing 12:48 (2000) l723
Halogen trimer synthons in crystal engineering: low-temperature X-ray and neutron diffraction study of the 1:1 complex of 2,4, 6-tris(4-chlorophenoxy)-1,3,5-triazine with tribromobenzene
Acta crystallographica. Section B, Structural science 56 (Pt 6) (2000) 1080-1084
Abstract:
The title complex has been studied using low-temperature X-ray (150 K) and neutron (100 K) diffraction. Molecules of the triazine host form a two-dimensional hexagonal network mediated by trigonally symmetric Cl(3) synthons having Cl.Cl interactions of 3.441 (3) A, a C-Cl.Cl angle of 165 degrees and a Cl.Cl-C angle of 105 degrees, close to the ideal values of 180 and 90 degrees, respectively. The guest molecules are of an appropriate size to fit the hexagonal networks and interact with the host via C-H.pi (phenyl) and C-Br.pi (phenyl) interactions which stabilize the overall structure. Both C-donor bond vectors are directed more closely towards the mid-point (X) of an individual aromatic bond, rather than the ring centroid, with H.X 2.817 (9) A and C-H.X 174.0 (9) degrees, and Br.X 3.353 (4) A and C-Br.X 158.1 (2) degrees.Teaching Crystallography to Reluctant Physicists
Acta Crystallographica Section A: Foundations and advances International Union of Crystallography (IUCr) 56:s1 (2000) s173-s173
Direct measurement of the thermal expansion of the Si-O bond by neutron total scattering
Journal of Physics Condensed Matter IOP Publishing 12:26 (2000) l425