investigate the possibility of the isomer or resonance structures. it turns out that in the case of one can easily construct an isomeric form that obeys the octet rule in the central atom is oxygen rather than carbon. it is that isomeric form of dase not exist in nature. as a general rule carbon atom always form a total of bonds put another way nonbonding electron pair on carbon atom are very. another useful rule of a similar nature is that if a species contains severalatom of one kind and one of the atom of the same kind will assume equivalent positions in the species. in for example the four o atoms are all equivalent and bonded to the S atom and not to one another