As shown in the top figure at right, the ideal or D 3h trigonal prism in which all six carbon atoms are equivalent is distorted to the C 3v structure observed by Seppelt " et al . " by opening up one triplet of methyl groups ( upper triangle ) to wider C-W-C angles ( 94-97?) with slightly shorter C-W bond lengths, while closing the other triplet ( lower triangle ) to 75-78?with longer bond lengths.
