Barium metaborate is a white crystalline powder with the chemical formula Ba(BO2)2, which has a variety of hydrate forms. It is soluble in water at high temperatures but almost insoluble in water at room temperature. Barium metaborate is stable in air, but it is damp and hydrolyzed. 

It is mainly used for the preparation of other borate compounds, as a catalyst and mordant, as well as for the preparation of optical glass, ceramics, coatings and electroplating solutions.

1. Optical Materials: Barium metaborate is an important optical material, especially known for its nonlinear optical properties. It is used in the manufacture of optical devices such as lasers and optical sensors.

2. Catalyst: In the chemical industry, barium metaborate can be used as a catalyst to facilitate the progress of chemical reactions.

3. Ceramic Materials: Due to its high temperature resistance and electrical insulating properties, barium metaborate is used as an additive in ceramic materials.

4. Paints & Plastics: Barium metaborate is also used as an ingredient in some coatings, as well as as as a filler in the plastics industry.

5. Electroplating Solution: In the electroplating process, barium metaborate can be used as a component of the electroplating solution to improve the quality and performance of the electroplating layer.

6. Mordant: In the textile industry, barium metaborate can be used as a mordant to help fix the dye on the fiber.

7. Preparation of other borates: Barium metaborate is also an important raw material for the preparation of other borate compounds.