LCP theory

In chemistry, ligand close packing theory (LCP theory), sometimes called the ligand close packing model describes how ligand – ligand repulsions affect the geometry around a central atom.[1] It has been developed by R. J. Gillespie and others from 1997 onwards [2] and is said to sit alongside VSEPR[1] which was originally developed by R. J. Gillespie and R Nyholm.[3] The inter-ligand distances in a wide range of molecules have been determined. The example below shows a series of related molecules:[4]

F-F distance (pm) O-F distance (pm) C-F bond length (pm) C=O bond length (pm)
CF4 216 132
O=CF3− 216 223 139 123
O=CF2 216 222 132 117

The consistency of the interligand distances (F-F and O-F) in the above molecules is striking and this phenomenon is repeated across a wide range of molecules and forms the basis for LCP theory.

  1. ^ a b Teaching the VSEPR model and electron densities R. J. Gillespie and C. F. Matta, Chem. Educ. Res. Pract. Eur.: 2001, 2, 73-90
  2. ^ Reinterpretation of the Lengths of Bonds to Fluorine in Terms of an Almost Ionic Model E A. Robinson, S A. Johnson, Ting-Hua Tang, and R J. Gillespie Inorg. Chem., 36 (14), 3022 -3030, 1997. ic961315b S0020-1669(96)01315-8
  3. ^ Inorganic stereochemistry Gillespie, R.J. & Nyholm, R.S. (1957). Quarterly Reviews of the Chemical Society, 11, 339-380 doi:10.1039/QR9571100339
  4. ^ Bonding and Geometry of OCF3−, ONF3, and Related Molecules in Terms of the Ligand Close Packing Model Gillespie RJ, Robinson EA, Heard GL. Inorg Chem. 1998 Dec 28;37(26):6884-6889 doi:10.1021/ic981037b