Analyzing experimental electron density with the localized-orbital locator.

The localized-orbital locator, which describes the features of bonding in terms of the local kinetic energy, is approximately expressed as a function of electron density and its first and second derivatives. Calculations based on accurate electron densities derived from X-ray diffraction data are carried out for crystals with different types of chemical bonds. It is demonstrated that the localized-orbital locator reveals the features of atomic interactions in a solid state and allows the covalent, ionic and van der Waals bonds to be distinguished.