Selenium-silicon bonds, lengths

Si-S bond lengths of 212.3 and 212.9 pm) and (PhSe Si (Si-Se bond lengths are 227.2 and 227.4 pm) includes a comprehensive list of the structures of silicon-sulphur and silicon-selenium compounds. These suggest a decrease in the Si—S bond length from 216 pm to 212 pm as the number of Si—S bonds in the molecule increases5. 

The barriers to methyl group rotation in tetramethyl silane and dimethylselenane are 1.4 and 1.5 kcal/mol respectively ). Bond lengths are carbon-silicon, 1.94, carbon-selenium 1.94, carbon-tellurium 2.14 based on the sum of covalent radii ). 

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