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  2. Electron affinity - Wikipedia

    en.wikipedia.org/wiki/Electron_affinity

    A list of the electron affinities was used by Robert S. Mulliken to develop an electronegativity scale for atoms, equal to the average of the electrons affinity and ionization potential. [2] [3] Other theoretical concepts that use electron affinity include electronic chemical potential and chemical hardness.

  3. Color difference - Wikipedia

    en.wikipedia.org/wiki/Color_difference

    As most definitions of color difference are distances within a color space, the standard means of determining distances is the Euclidean distance.If one presently has an RGB (red, green, blue) tuple and wishes to find the color difference, computationally one of the easiest is to consider R, G, B linear dimensions defining the color space.

  4. Mulliken population analysis - Wikipedia

    en.wikipedia.org/wiki/Mulliken_population_analysis

    Mulliken charges arise from the Mulliken population analysis [1] [2] and provide a means of estimating partial atomic charges from calculations carried out by the methods of computational chemistry, particularly those based on the linear combination of atomic orbitals molecular orbital method, and are routinely used as variables in linear regression (QSAR [3]) procedures. [4]

  5. Electronegativity - Wikipedia

    en.wikipedia.org/wiki/Electronegativity

    Electronegativity, symbolized as χ, is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. [1] An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the ...

  6. Chemical polarity - Wikipedia

    en.wikipedia.org/wiki/Chemical_polarity

    Ionic bonds generally occur when the difference in electronegativity between the two atoms is greater than 2.0; Pauling based this classification scheme on the partial ionic character of a bond, which is an approximate function of the difference in electronegativity between the two bonded atoms. He estimated that a difference of 1.7 corresponds ...

  7. Electron density - Wikipedia

    en.wikipedia.org/wiki/Electron_density

    Electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial variables and is typically denoted as either ρ ( r ) {\displaystyle \rho ({\textbf {r}})} or n ( r ) {\displaystyle n ...

  8. Bent's rule - Wikipedia

    en.wikipedia.org/wiki/Bent's_rule

    Bent's rule can be extended to rationalize the hybridization of nonbonding orbitals as well. On the one hand, a lone pair (an occupied nonbonding orbital) can be thought of as the limiting case of an electropositive substituent, with electron density completely polarized towards the central atom.

  9. Ab initio quantum chemistry methods - Wikipedia

    en.wikipedia.org/wiki/Ab_initio_quantum...

    The problem of computational expense can be alleviated through simplification schemes. [7] In the density fitting scheme, the four-index integrals used to describe the interaction between electron pairs are reduced to simpler two- or three-index integrals, by treating the charge densities they contain in a simplified way.