It is available as a hydrate or dehydrated form, as white powder or colorless crystals.

Barium borate was discovered and developed by Chen Chuangtian and others of the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences.

Barium borate exists in three major crystalline forms: alpha, beta, and gamma.

β-Barium borate (BBO) differs from the α form by the positions of the barium ions within the crystal.

It has good mechanical properties and is a suitable material for high-power ultraviolet polarization optics.

[1] Beta barium borate, β-BaB2O4, is a nonlinear optical material transparent in the range ~190–3300 nm.

[1][2] The material exhibits a melting temperature of 1268 K,[6] with anisotropic thermal expansion coefficients:

[8] Barium borate has strong negative uniaxial birefringence and can be phase-matched for type I (ooe) second-harmonic generation from 409.6 to 3500 nm.

In the liquid state the relative fractions of sp2 and sp3 boron are temperature-dependent, with the trigonal planar coordination favored at higher temperatures.

The prepared γ-barium borate contains water of crystallization that can not be completely removed by drying at 120 °C.

BBO prepared by this method does not contain trace amounts of BaB2O2[10] BBO crystals for nonlinear optics can be grown from fluxed melt of barium borate, sodium oxide and sodium chloride.

[12] Thin films of beta-barium borate can be prepared by sol-gel synthesis.

Quantum linked photons are producible with beta barium borate.

[15] It is added to paints, coatings, adhesives, plastics, and paper products.