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Lipinski's rule of five, also known as Pfizer's rule of five or simply the rule of five (RO5), is a rule of thumb to evaluate druglikeness or determine if a chemical compound with a certain pharmacological or biological activity has chemical properties and physical properties that would likely make it an orally active drug in humans.
In crystallography, materials science and metallurgy, Vegard's law is an empirical finding (heuristic approach) resembling the rule of mixtures.In 1921, Lars Vegard discovered that the lattice parameter of a solid solution of two constituents is approximately a weighted mean of the two constituents' lattice parameters at the same temperature: [1] [2]
The handbook was originally published in 1928 by the Chemical Rubber Company (now CRC Press) as a supplement (Mathematical Tables) to the CRC Handbook of Chemistry and Physics. Beginning with the 10th edition (1956), it was published as CRC Standard Mathematical Tables and kept this title up to the 29th edition (1991).
Shape of water molecule showing that the real bond angle 104.5° deviates from the ideal sp 3 angle of 109.5°. In chemistry, Bent's rule describes and explains the relationship between the orbital hybridization and the electronegativities of substituents. [1] [2] The rule was stated by Henry A. Bent as follows: [2]
[2]: 561 This rule tends to increase the distance between highly charged cations, so as to reduce the electrostatic repulsion between them. One of Pauling's examples is olivine , M 2 SiO 4 , where M is a mixture of Mg 2+ at some sites and Fe 2+ at others.
A good rule of thumb for utilizing this label is the 5/20 rule. Under this rule, less healthy nutrients should be kept at 5% DV or less. Healthier nutrients, however, should be 20% DV or greater.
The Lorentz rule was proposed by H. A. Lorentz in 1881: [5] = + The Lorentz rule is only analytically correct for hard sphere systems. Intuitively, since , loosely reflect the radii of particle i and j respectively, their averages can be said to be the effective radii between the two particles at which point repulsive interactions become severe.
For alloys containing transition metal elements there is a difficulty in interpretation of the Hume-Rothery electron concentration rule, as the values of e/a values (number of itinerant electrons per atom) for transition metals have been quite controversial for a long time, and no satisfactory solutions have yet emerged. [9] [10]