In the previous post, I found intriguing the mechanism by which methane (CH ₄ ) inverts by transposing two of its hydrogens. Here I take a look at silane, SiH ₄ . It appears it is a three-stage process! Firstly, silane eliminates molecular hydrogen to form a molecular complex between H _{2 and SiH 2} (DOI: 10.14469/hpc/2290). The barrier (~60 kcal/mol) is very much lower than with methane.

This is a spin-off from the table I constructed here for further chemical examples of the classical/non-classical norbornyl cation conundrum. One possible entry would include the transition state for inversion of methane via a square planar geometry as compared with e.g. NiH ₄ for which the square planar motif is its minimum.