Charge densities come of age.

Debyes statement preceded the devel-opment of quantum mechanics andBorns definition of electron probabilitydistribution, but correctly assumed thatthe electron distribution was an observ-able that had become accessible. Inter-estingly, it took the better part of acenturyforthisvisiontoberealizedandfor X-ray charge-density analysis tobecome a true analytical technique thatwas capable of providing quantitativeinsight into controversial issues andsufficiently rapid to be applicable to aseries of related problems. In 1990 wewrote, “At present, charge-densityanalysisisfarfromaroutinetechnique”,pointing out the need for time-consum-ing collection of large data sets and thelimitations in accuracy of the experi-mental measurements.

[1]  W. J. Orville-Thomas.  Atoms in Molecules — a Quantum Theory , 1996 .

[2]  M. Messerschmidt,et al.  Electron density and bonding at inverted carbon atoms: an experimental study of a [1.1.1]propellane derivative. , 2005, Angewandte Chemie.

[3]  R. Bader,et al.  Theoretical analysis of hydrocarbon properties. 1. Bonds, structures, charge concentrations, and charge relaxations , 1987 .

[4]  D. Jayatilaka,et al.  Wavefunctions derived from experiment. II. A wavefunction for oxalic acid dihydrate. , 2001, Acta crystallographica. Section A, Foundations of crystallography.

[5]  G. Frenking,et al.  The nature of the bonding in transition-metal compounds. , 2000, Chemical reviews.

[6]  D. Jayatilaka,et al.  Wavefunctions derived from experiment. IV. Investigation of the crystal environment of ammonia. , 2002, Acta crystallographica. Section A, Foundations of crystallography.

[7]  Daniel J. Grimwood,et al.  Wave functions derived from experiment. V. Investigation of electron densities, electrostatic potentials, and electron localization functions for noncentrosymmetric crystals , 2003, J. Comput. Chem..

[8]  D. Jayatilaka,et al.  Wavefunctions derived from experiment. I. Motivation and theory. , 2001, Acta crystallographica. Section A, Foundations of crystallography.

[9]  M. Messerschmidt,et al.  High-resolution synchrotron data collection for charge-density work at 100 and 20 K. , 2004, Acta crystallographica. Section A, Foundations of crystallography.

[10]  R. Bader.  Atoms in molecules : a quantum theory , 1990 .

[11]  J. Michl,et al.  Bicyclo[1.1.1]pentanes, [n]Staffanes, [1.1.1]Propellanes, and Tricyclo[2.1.0.0(2,5)]pentanes. , 2000, Chemical reviews.

[12]  Dieter Cremer,et al.  Chemische Bindungen ohne Bindungselektronendichte -reicht die Differenzdichteanalyse zur Bindungsbeschreibung aus?† , 1984 .

[13]  P. Coppens,et al.  The Past and Future of Experimental Charge Density Analysis , 1991 .

[14]  Zobel,et al.  Accurate experimental electronic properties of dl-proline monohydrate obtained within 1 Day , 1998, Science.

[15]  D. Jayatilaka,et al.  Electron localization functions obtained from X-ray constrained Hartree-Fock wavefunctions for molecular crystals of ammonia, urea and alloxan. , 2004, Acta crystallographica. Section A, Foundations of crystallography.

[16]  P. Debye,et al.  Zerstreuung von Röntgenstrahlen , 1915 .

[17]  R. Bader,et al.  Spatial localization of the electronic pair and number distributions in molecules , 1975 .

[18]  Philip Coppens,et al.  X-ray charge densities and chemical bonding , 1997 .

[19]  Elfi Kraka,et al.  Chemical Bonds without Bonding Electron Density — Does the Difference Electron‐Density Analysis Suffice for a Description of the Chemical Bond? , 1984 .

[20]  A. Sironi,et al.  Electron density of semi-bridging carbonyls. Metamorphosis of CO ligands observed via experimental and theoretical investigations on [FeCo(CO)(8)](-). , 2002, Journal of the American Chemical Society.

[21]  Adam I. Stash,et al.  Determination of the electron localization function from electron density , 2002 .

[22]  Axel D. Becke,et al.  A Simple Measure of Electron Localization in Atomic and Molecular-Systems , 1990 .

[23]  Davide M. Proserpio,et al.  Experimental Electron Density in a Transition Metal Dimer: Metal−Metal and Metal−Ligand Bonds , 1998 .

[24]  Günter Szeimies,et al.  Elektronendichte und Bindungsverhältnisse an invertierten Kohlenstoffatomen: eine experimentelle Studie an einem [1.1.1]Propellanderivat† , 2005 .