Tetrahydroxyborate has a symmetric tetrahedral geometry,[3]: p.203–205  isoelectronic with the hypothetical compound orthocarbonic acid (C(OH)4).

Tetrahydroxyborate acts as a weak Brønsted–Lowry base because it can assimilate a proton (H+), yielding boric acid with release of water: It can also release a hydroxide anion HO−, thus acting as a classical Arrhenius base: Thus, when boric acid is dissolved in pure (neutral) water, most of it will exist as tetrahydroxyborate ions.

[citation needed] In aqueous solution, the tetrahydroxyborate anion reacts with cis-vicinal diols (organic compounds containing similarly-oriented hydroxyl groups in adjacent carbon atoms), (R1,R2)=C(OH)−C(OH)=(R3,R4)) such as mannitol, sorbitol, glucose and glycerol, to form anion esters containing one or two five-member −B−O−C−C−O− rings.

This is a reliable method to assay the amount of borate content present in the solution.

Oxidation of tetrahydroxyborate gives the perborate anion [B2O4(OH)4]2−: When heated to a high temperature, tetrahydroxyborate salts decompose to produce metaborate salts and water, or to produce boric acid and a metal hydroxide: Tetrahydroxyborate salts are produced by treating boric acid with an alkali such as sodium hydroxide, with catalytic amounts of water.