The molecular interaction of $Mo_2(OR)_4({mu}-OR)_2$$ unit has been studied for carbonyl and acetylene ligands by means of extended Huckel calculations. We have extended the extended Hckel calculations to unknown apex bridged $Mo_2(OR)_6({mu}-X)$ complexes (X = $SO_2$H, and Cl) in order to compare the stability of the complexes. In the $C_2H_2$and H apex bridged complexes, one finds a relatively small HOMO-LUMO gap. However, both complexes are stabilized due to Jahn-Teller distortion. The stability of both complexes is comparable to that of $Mo_2(OR)_6(CO)$ complex. The comparisons and predictions in the stability of known and unknown complexes are the subject of this study.