Borinic acid

Borinic acid H
2BOH, also known as boronous acid, is an oxyacid anion of boron with formula H
2BOH. Borinate is the associated anion of boron with formula H
2BO−, however being a lewis acid the form in basic solution is H
2B(OH)−
2.

Borinic acid can be formed as the first step in the hydrolysis of diborane. BH₃+H₂O → H₂BOH + H₂ Borinic acid itself is unstable and only lasts for a few seconds during the hydrolysis reaction. However, by using microwave spectroscopy various properties can be determined. The B-O distance is 1.352 Å, O-H distance 0.96 Å, B-H length is probably 1.2 Å. The angle between bonds at the oxygen atom BOH = 112° and the angles at boron are cis-HBO 121°, and trans-HBO = 117°. The dipole moment is 1.506 Debye.