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In the analysis of the molecular formula of organic molecules, the degree of unsaturation (DU) (also known as the index of hydrogen deficiency (IHD), double bond equivalents (DBE), or unsaturation index [1]) is a calculation that determines the total number of rings and π bonds. A formula is used in organic chemistry to
Hexamethylene diisocyanate (HDI) is the organic compound with the formula (CH 2) 6 (NCO) 2. It is classified as an diisocyanate. It is a colorless liquid. [2] It has sometimes been called HMDI [3] but this not usually done to avoid confusion with Hydrogenated MDI.
The invariance properties of molecular descriptors can be defined as the ability of the algorithm for their calculation to give a descriptor value that is independent of the particular characteristics of the molecular representation, such as atom numbering or labeling, spatial reference frame, molecular conformations, etc. Invariance to molecular numbering or labeling is assumed as a minimal ...
Hansen solubility parameters were developed by Charles M. Hansen in his Ph.D thesis in 1967 [1] [2] as a way of predicting if one material will dissolve in another and form a solution. [3]
In gas chromatography, the Kovats retention index (shorter Kovats index, retention index; plural retention indices) is used to convert retention times into system-independent constants. The index is named after the Hungarian-born Swiss chemist Ervin Kováts , who outlined the concept in the 1950s while performing research into the composition ...
The simplest case refers to the formation of a strictly linear polymer by the reaction (usually by condensation) of two monomers in equimolar quantities. An example is the synthesis of nylon-6,6 whose formula is [−NH−(CH 2) 6 −NH−CO−(CH 2) 4 −CO−] n from one mole of hexamethylenediamine, H 2 N(CH 2) 6 NH 2, and one mole of adipic acid, HOOC−(CH 2) 4 −COOH.
In coordination chemistry and crystallography, the geometry index or structural parameter (τ) is a number ranging from 0 to 1 that indicates what the geometry of the coordination center is. The first such parameter for 5-coordinate compounds was developed in 1984. [ 1 ]
A uniform polymer (often referred to as a monodisperse polymer) is composed of molecules of the same mass. [5] Nearly all natural polymers are uniform. [6] Synthetic near-uniform polymer chains can be made by processes such as anionic polymerization, a method using an anionic catalyst to produce chains that are similar in length.