The structural properties of the 4Bi(2)O(3) center dot B2O3 glass were investigated by FT-IR spectroscopy and quantum chemical calculations. The main results reveal that the coordination polyhedrons of the bismuth ion from the [BiO6] structural units and of the boron ion from the [BO4] groups are irregular. Accordingly, the [BiO6] and [BO4] structural units in the studied glass matrix have a complex structural role that makes possible the formation of the vitreous system.