Pyridine 1:1 adducts of urea (Z′ = 1) and thiourea (Z′ = 8)

During our studies of urea and thiourea adducts, we noticed that no adducts with unsubstituted pyridine had been structurally investigated. The 1:1 adduct of pyridine and urea, C5H5N·CH4N2O, crystallizes in the P21/c space group with Z = 4. The structure is of a standard type for urea adducts, whereby the urea molecules form a ribbon, parallel to the a axis, consisting of linked R 2 2(8) rings, and the pyridine molecules are attached to the periphery of the ribbon by bifurcated (N—H...)2N hydrogen bonds. The 1:1 adduct of pyridine and thiourea, C5H5N·CH4N2S, crystallizes in the P21/n space group, with Z = 32 (Z′ = 8). The structure displays similar ribbons to those of the urea adduct. There are two independent ribbons parallel to the b axis at z ≃ 0 and 1 \over 2, and three at z ≃ 1 \over 4 and 3 \over 4; the latter are crosslinked to form a layer structure by additional long N—H...S interactions, which each formally replace one branch of a bifurcated hydrogen-bond system.

Separation of urea adducts in the analysis of complex mineral fertilisers

An investigation of the analytical separation of free urea from its additive compounds with H

Crystal structures of Cd(ReO4)2 · 4Urea, Cd(ReO4)2 · 6Urea and Ca(ReO4)2 · 5Urea. Synthesis and characterization of urea adducts from the systems M(ReO4)2-Urea-H2O, M = Ca, Sr, Ba, Pb and Cd

The crystal structutes of Cd(ReOWith the synthesis and X-ray analysis of these new urea adducts the investigation of the systems M(ReO