Boric acid (boron hydroxide acid) — the weak acid having chemical formula of H3BO3.
Colourless crystal substance in the form of flavourless scales, has layered triclinic lattice in which molecules of acid are connected by hydrogen bonds in flat layers, layers are connected among themselves by intermolecular bonds (d = 0,318 nanometers).
Metaboric acid (HBO2) also represents colourless crystals. It exists in three modifications — the steadiest γ - HBO2 with cubical lattice, β - HBO2 with monoklinny lattice and α - HBO2 with rhombic lattice.
When heating boron hydroxide acid loses water and at first passes into metaboric acid, then into tetraboric H2B4O7. At further heating it is dehydrated to boric anhydride.
Aqueous solutions of boric acid are mix of polyboric acids of the general formula N3m - 2nvmo3m - n.
