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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.[5]
- ^ 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
- ^ 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
- ^ Inorganic stereochemistry Gillespie, R.J. & Nyholm, R.S. (1957). Quarterly Reviews of the Chemical Society, 11, 339-380 doi:10.1039/QR9571100339
- ^ 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
- ^ Rowsell, Bryan D.; Gillespie, Ronald J.; Heard, George L. (1999-10-01). "Ligand Close-Packing and the Lewis Acidity of BF 3 and BCl 3". Inorganic Chemistry. 38 (21): 4659–4662. doi:10.1021/ic990713m. ISSN 0020-1669.
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