  A precise discussion of a single bond requires consideration of two-particle
wave function for the particles involved. Here we define and determine
rigorously the intrinsic covalency and connected characteristics on the
canonical example of \ch{H2} molecule. This is achieved by starting from
analytic form for the two--particle wave function for electrons forming the
bond, in which we single out the atomic contribution (\textit{atomicity}) in an
unequivocal manner. The presence the of atomicity and ionicity factors
complements the existing attributes of the bond. In this way, a gradual
evolution of the molecular state to its two-atomic correspondant is traced
systematically with increasing interatomic distance. In effect, a direct
relation to the onset of incipient Mott-Hubbard atomicity (\textit{Mottness})
to the intrinsic covalency and ionicity is established. This goal is achieved
by combining the single--particle wave function readjustment with a
simultaneous determination of two--particle states in the particle
(second--quantization) representation.
