Randić's molecular connectivity index
Introduction The '''Randić index''', also known as the '''connectivity index''', of a graph is the sum of bond contributions  where  and  arethe degrees of the vertices making bond ''i'' ~ ''j''.
History This graph invariant was introduced by Milan Randić in 1975.It is often used in chemoinformatics for investigations of organic compounds.
Notes
References *Roberto Todeschini, Viviana Consonni (2009) "Molecular Descriptors for Chemoinformatics", ''Wiley-VCH'', *.de:Randić-Index