The structure and bonding of the lithium metaborate (LiBO2) molecule. An ab initio study

Results of ab initio calculations at different levels of accuracy are reported for the lithium metaborate molecule. The gas phase LiBO2 is shown to have a linear (C∞h) conformation. The C2V structure represents a saddle point for the Li-migration. No Cs structure has been found as a stationary point on the energy surface. Comparison between computed and observed vibrational frequencies suggests that a lowering of the molecular symmetry (C∞h → Cs) can take place under matrix conditions. The linear LiBO2 is predicted to be a very stable species with regard to fragmentation into Li+ and BO2− (dissociation energy of 143.4 kcal mol−1 at MP4SDQ/6-31 + G* plus ZPE contributions) but the migration of lithium from one oxygen atom to another is an easy process (energy barrier of 8.2 kcal mol−1). Some molecular properties are computed and commented on.