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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.
[4] [5] Bent's rule can be justified through the relative energy levels of s and p orbitals. Bent's rule represents a modification of VSEPR theory for molecules of lower than ideal symmetry. [6] For bonds with the larger atoms from the lower periods, trends in orbital hybridization depend strongly on both electronegativity and orbital size.
The order of sequence of atomic orbitals (according to Madelung rule or Klechkowski rule) can be remembered by the following. [2] Order in which orbitals are arranged by increasing energy according to the Madelung rule. Each diagonal red arrow corresponds to a different value of n + l.
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]
They also provide a shuttle for the efficient transfer of one proton in the formation of intermediate 5. The above mechanism is consistent with all available experimental evidence. [ 3 ] The equilibrium between species 1 and 2 is supported by 18 O Isotopic labeling experiments.
In materials science, a general rule of mixtures is a weighted mean used to predict various properties of a composite material. [ 1 ] [ 2 ] [ 3 ] It provides a theoretical upper- and lower-bound on properties such as the elastic modulus , ultimate tensile strength , thermal conductivity , and electrical conductivity . [ 3 ]
In chemistry, the lever rule is a formula used to determine the mole fraction (x i) or the mass fraction (w i) of each phase of a binary equilibrium phase diagram. It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line. [1]
Bredt's rule is the empirical observation that such molecules only form in large ring systems. For example, two of the following norbornene isomers violate Bredt's rule, and are too unstable to prepare: Bridgehead atoms violating Bredt's rule in red. The rule is named after Julius Bredt, who first discussed it in 1902 [1] and codified it in ...