Within the scope of two physically different approaches (solid-state and quantum-chemical) adsorption of nitrogen atom and nitrogen dioxide and ammonia mole-cules on silicon carbide are considered. In solid-state approach with the use of Haldane-Anderson model for the densities of state of 4H- and 6H-SiC polytypes it is shown that the binding energies for N and N2 are 6 and 3 eV correspondingly. In quantum-chemical approach for the two-atom surface molecule model for N adsorption the binding energy values are 6 eV for adsorption on C-face and 4 eV for adsorption on Si-face. It is demonstrated that the charge transfer between ad-sorbate and substrate for all the cases considered are negligible. It is proposed that as in the case of NH3 on Si(100) adsorption for SiC substrate ammonia molecule dissociates and H atoms passivate SiC sp3 orbitals.