openbabel/openbabel — pull request #84 by ghutchis (2014-07-26 03:02:20+00:00)
Title: Use averaged bond order corrections from Pyykko and Atsumi 2009.

Slight modifications from previous versions, but likely better
overall, since they're systematically derived.
http://dx.doi.org/10.1002/chem.200901472
http://www.chem.helsinki.fi/~pyykko/Radii09.pdf