Carbon tetrabromide, crystal structure

Blackstock, S. C., J. P. Lorand, and J. K. Kochi. 1987. Charge Transfer Interactions of Amines with Tetrahalomethanes. X-ray Crystal Structures of the Donor-Acceptor Complexes of Quinuclidine and Diazabicyclo-[2.2.2]octane with Carbon Tetrabromide. J. Qrg. Chem. 52,1451. 

Figures 20.4.4(a) and 20.4.4(b) illustrate the crystal structure of the 1 1 complex of tetraphenylmethane and carbon tetrabromide. The nodes comprise C(C6H5)4 and CBr4 molecules, and the each linking rod is the weak interaction between a Br atom and a phenyl group. The hexamethylenetetramine-like structural unit is outlined by broken lines. Figures 20.4.4(c) and 20.4.4(d) show the crystal structure of tetrakis(4-bromophenyl)methane, which has a distorted diamondoid network based on the hexamethylenetetramine building unit. If the synthon composed of the aggregation of four Br atoms is considered as a node, then two kinds of nodes (Br4 synthon and quatenary C atom) are connected by rods consisting of p-phenylene moeities.

This sudden drop in the velocity is associated with the carbon tetrabromide molecule suddenly gaining the freedom to rotate on its axis without the ability to undergo translation. The onset of translation is marked by the melting transition at 366.4 °C. The tetrahedral molecule below 320.9 °C is locked into the crystal structure and the C-Br bonds point in well-defined directions. At 320.9 °C the lattice expansion allows the molecule to rotate on its lattice point and being a pseudo-spherical molecule, the average force field has an... 

Blackstock SC, Loiand JP, Kochi JK (1987) Charge transfer interactions of amines with letrahalomethanes - X-ray crystal-structures of the donra-acceptra cranplexes of quinuclidine and diazabicyclo[2.2.2]octane with carbon tetrabromide. J Org Chem 52 1451-1460... 

Strieter FJ, Templeton DH (1962) Crystal structure of the carbon tetrabromide-p-xylene complex. J Chem Phys 37 161-164... 

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