Barium carbonate, with the chemical formula BaCO3, is a chemical compound composed of barium (Ba) cations and carbonate (CO3^2-) anions. It is a white, odorless, and insoluble solid at room temperature. Barium carbonate occurs naturally as the mineral witherite, but it can also be produced synthetically.

Some key properties and uses of barium carbonate include:

1. Ceramic Industry: Barium carbonate is used in the ceramic industry as a glaze and flux. It helps lower the melting point of certain ceramic materials and enhances the brightness and durability of ceramic glazes.
2. Glass Manufacturing: It is used in the glass industry to produce certain types of optical and specialty glasses.
3. Rat Poison: Historically, barium carbonate was used as a rat poison due to its toxicity. However, its use as a pesticide has been restricted or banned in many countries due to environmental and health concerns.
4. Laboratory Reagent: Barium carbonate is used as a laboratory reagent in certain chemical reactions and analytical procedures.

Barium carbonate is toxic if ingested or inhaled, and it can be harmful to the environment. Therefore, it should be handled with care, and safety precautions, such as good ventilation and the use of personal protective equipment, should be followed when working with this compound.

In modern times, barium carbonate is mainly used in specialized industrial processes, such as ceramics and glass manufacturing. Its use as a rat poison has been largely replaced by safer alternatives, and its toxicity warrants careful handling and controlled use.