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  2. Bond valence method - Wikipedia

    en.wikipedia.org/wiki/Bond_valence_method

    The bond valence model is an extension of the electron counting rules and its strength lies in its simplicity and robustness. Unlike most models of chemical bonding, it does not require a prior knowledge of the atomic positions and so can be used to construct chemically plausible structures given only the composition.

  3. UNIFAC - Wikipedia

    en.wikipedia.org/wiki/UNIFAC

    To alleviate this problem, free energy prediction models, such as UNIFAC, are employed to predict the system's energy based on a few previously measured constants. It is possible to calculate some of these parameters using ab initio methods like COSMO-RS , but results should be treated with caution, because ab initio predictions can be off.

  4. Non-random two-liquid model - Wikipedia

    en.wikipedia.org/wiki/Non-random_two-liquid_model

    The non-random two-liquid model [1] (abbreviated NRTL model) is an activity coefficient model introduced by Renon and Prausnitz in 1968 that correlates the activity coefficients of a compound with its mole fractions in the liquid phase concerned. It is frequently applied in the field of chemical engineering to calculate phase equilibria.

  5. Molecular model - Wikipedia

    en.wikipedia.org/wiki/Molecular_model

    A molecular model is a physical model of an atomistic system that represents molecules and their processes. They play an important role in understanding chemistry and generating and testing hypotheses .

  6. Computational chemistry - Wikipedia

    en.wikipedia.org/wiki/Computational_chemistry

    However, computational chemistry involves the usage of computer programs and additional mathematical skills in order to accurately model various chemical problems. In theoretical chemistry, chemists, physicists, and mathematicians develop algorithms and computer programs to predict atomic and molecular properties and reaction paths for chemical ...

  7. Solvent model - Wikipedia

    en.wikipedia.org/wiki/Solvent_model

    In computational chemistry, a solvent model is a computational method that accounts for the behavior of solvated condensed phases. [ 1 ] [ 2 ] [ 3 ] Solvent models enable simulations and thermodynamic calculations applicable to reactions and processes which take place in solution.

  8. Group-contribution method - Wikipedia

    en.wikipedia.org/wiki/Group-contribution_method

    The simplest form of a group-contribution method is the determination of a component property by summing up the group contributions : [] = +.This simple form assumes that the property (normal boiling point in the example) is strictly linearly dependent on the number of groups, and additionally no interaction between groups and molecules are assumed.

  9. Ball-and-stick model - Wikipedia

    en.wikipedia.org/wiki/Ball-and-stick_model

    A plastic ball-and-stick model of proline. In chemistry, the ball-and-stick model is a molecular model of a chemical substance which displays both the three-dimensional position of the atoms and the bonds between them. [1] The atoms are typically represented by spheres, connected by rods which represent the bonds.