When orthoborate salts are dissolved in water, the anion converts mostly to boric acid  and other hydrogen-containing borate anions, mainly tetrahydroxyborate . The reactions of orthoborate in solution are therefore mostly those of these compounds.
In particular, these reactions include the condensation of tetrahydroxoborate with cis-vicinal diols such as mannitol, sorbitol, glucose and glycerol, to form relatively stable anion esters. This reaction is used in analytic chemistry to determine the concentration of borate anions.