Relation between NH and other Simple Molecules

Relations between abundances of interstellar NH molecule and other diatomic species as OH, CH, CH⁺ and molecular/atomic hydrogen are presented based on 16 available sight-lines. Spacial correlations between column densities of diatomic molecules suggest that the NH molecule is rather related to interstellar CN (correlation coefficient equal to 0.82±0.09). A good relation with molecular hydrogen with correlation coefficient equal to 0.79±0.12 is also presented.