Structures of XH 32+ (X=C, Si and Ge) and isoelectronic XH 3+ (X=B, Al and Ga)

Abstract

Ab initio calculations at the MP2/6–31G** and QCISD(T)/6–311G** levels were carried out to calculate the structures of XH 3 2+ (X=C, Si and Ge) and XH 3 + (X=B, Al and Ga). Energy comparison shows that the global minimum structures of XH 3 2+ (X=Si and Ge) and XH 3 + (X=Al and Ga) are not of C 2v symmetry ( 2–3a and 5–6a) but of C s symmetry ( 2–3b and 5–6b) with 3c–2e bonds. As we move to higher analogs of a given series, the 3c–2e bonded structures are increasingly more favorable than the corresponding C 2v structures.