The three lowest lying isomers of Al2H2, the planar dibridged hydrogen D-2h form, the planar vinylidene-like C-2v form, and the planar monobridged hydrogen C-s form, were examined using high level ab initio methods. The highest level treatment of the energetics and harmonic vibrational frequencies, TZ2Pf CCSD(T), suggests that the dibridged and monobridged forms of Al2H2 were detected by matrix isolation infrared studies (J. Phys. Chem. 97, 10 295 1993).