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An attempt has been made to refine electron diffraction data collected at 130°for cyclodecane in terms of a simplified boat-chair-boat (BCB) model of C2h symmetry. The resulting structural parameters were: rg(C-C)£V = 1.545 ± 0.003 A, rg(C-H)av = 1.115 ± 0.003Á, ZCCH(av) = 108.7 ± 1.0°, /CAA = 114.6 ± 1.2°, and ZCiC2C3 = ZC2C3C4 = 116.9 ± 0.9°. The resolution factors for the short and long camera distances were 0.99 and 0.97, respectively. It is readily conceivable that the excellence of the fit of this model is fortuitous and misleading, however, since electron diffraction analyses rarely yield a unique structure for a molecule of this size and flexibility. An alternative analytical approach has been adopted in which detailed structures and selected thermodynamic properties have been calculated for 12 stable conformations of cyclodecane. Theoretical radial distribution curves have been generated for the four conformations of lowest energy. Least-squares analysis of the experimental radial distribution curve utilizing the four theoretical curves has indicated the following composition: BCB 49 ± 3%, twist-boat-chair (TBC) 35 ± 3%, TBCC 8 ± 4%, and BCC 8 ± 4%. The two methods of analysis have been critically discussed, particularly from the point of view of the analysis of multiconformational molecules of cyclodecane's complexity.(1) (a) North Dakota State University; (b) Indiana University.(2) See, for example, E.

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