The Crystal Structure of Selenourea at 20°C and ar -100°C

Abstract

<p>The trigonal form of selenourea has been examined by X-ray crystallographic methods both at room temperature and at a lower temperature ( -100°C) . The lattice parameters of earlier workers have been refined and the space group assignment, which requires nine crystallographically distinct SeC(NH2)2 molecules, confirmed. The crystal structure was solved using a novel Patterson technique and differences Fourier syntheses, and was refined by least squares using three - dimensional data obtained 0 at -100°C. Both the molecular dimensions and the crystal structure found are compared to other members of the urea series, and the similarity of the crystal structure to the urea- and thioureahydrocarbon complexes discussed. Evidence is presented of N-H...Se hydrogen bonds, supporting their recent discovery in chemically related compounds.</p>