
%0 Journal Article
%A Riggs, NV 
%A Radom, L 
%T <i>Ab Initio</i> Studies on Amides: Cyanamide, Dicyanamide and Tricyanamide
%J Australian Journal of Chemistry
%D 1985/06/01
%V 38
%N 6
%P 835-840
%K 
%R https://doi.org/10.1071/CH9850835
%U https://www.publish.csiro.au/paper/CH9850835 
%X Optimization of the geometry of cyanamide with the 3-21G basis set leads to a planar (C2v) structure, whereas the STO-3G, 6-31G* and 6- 31G** basis sets lead to a pyramidal structure at the amido -nitrogen atom. The 6-31G* and 6-31G** geometries are reasonably close to the experimental geometry, and the calculated barriers to inversion (4.5 and 3.4 kJ mol-1, respectively) are also close to experimental values (5.4-5.6 kJ mol-1), but the STO-3G value (13.9 kJ mol-1) is much too high. Dicyanamide is far from planar at the STO-3G level but planar at the more definitive 6-31G* level, whereas tricyanamide is planar even at the STO-3G level. The prediction is that, in contrast to cyanamide itself, dicyanamide and tricyanamide are planar molecules. Calculated increases in N-C bond-lengths and decreases in C&#8801;N bond-lengths for dicyanamide and tricyanamide as compared with the planar form of cyanamide are used to predict experimental lengths for these bonds in di - and tri- cyanamide. 
