The crystal structure of 3,3,4,4-tetrahydrofurantetrol (an application of vector verification)

A three-dimensional crystal structure analysis of 3,3,4,4-tetrahydrofurantetrol determined that this molecule exists in a twisted configuration (44 ring twist), that the space group is P(4)2 sub 1c with eight molecules per unit cell, and that the molecules lie in layers which are held together and interconnected by hydrogen bonds. The trial model was obtained by a new method called vector verification. The method systematically checks, by applying space group symmetry and other conditions, each point in a three-dimensional grid in electron density space. At each grid point, a series of vectors is computed and compared with the observed Patterson function, and only if the vectors exist in the Patterson map can the grid point be considered as a possibility for an atomic position. The trial model was refined using full matrix least squares to a final model having an agreement index of 0.11. (Author)