Nine compounds, namely Li3BO3, alpha-Li4B2O5, beta-Li4B2O5, Li6B4O9, alpha-LiBO2, Li2B4O7, Li3B7O12, LiB3O5 and Li2B8O13 in the Li2O-B2O3 system have been synthesized and characterized. The unit-cell parameters, density and solubility in water at room temperature of all the compounds are reported. The densities of the compounds were found to be in the 1.90-2.50 g cm(-3) range, while their solubility in water at room temperature was in the 0.91-8.64x10(-2) g cm(-3) range. Determination of the thermal stability of the compounds by quenching and differential thermal analysis (DTA) showed that only alpha-LiBO2 and Li2B4O7 retained their original symmetry up to their congruent melting at 1121 and 1188 K, respectively, in air.