The function, STO-nG is found as the most common minimal basis set, where n is an integer, e.g. STO-3G, STO-4G etc. The value "n" is used to represent the available primitive Gaussian functions that are contained within a single basis function. In the minimal basis set, the same number of primitive Gaussian functions comprise the core and valence orbitals, therefore, typically giving rough results that are not sufficient for predicting the chemical properties.