Type 1 Lewis Acid/Base Complexation Chemistry
Type 1 complexes form when Proton Lewis acids complex with s-HOMO Lewis bases (hydride ions, hydrogen or deuterium or tritium isotopic homologs). There are therefore of two general types of Type 1 Lewis acid/base complex: H2 and [H3]+. Both types of complex possess two electrons in a single MO, the 1s HOMO.

For more information look in the Chemogenesis webbook sections on Lewis acids and Lewis bases and the Lewis acid/base interaction matrix.