Barium oxalate, with the chemical formula BaC2O4, is a chemical compound composed of barium (Ba) cations and oxalate (C2O4^2-) anions. It is a white crystalline solid that is sparingly soluble in water.

Some key properties and uses of barium oxalate include:

1. Laboratory Reagent: Barium oxalate is used as a laboratory reagent in various chemical reactions and analytical procedures.
2. Poisoning Antidote: Historically, barium oxalate was used as an antidote for certain types of poisoning, particularly poisoning from soluble salts of heavy metals like lead and copper. It works by forming insoluble complexes with these metals, thereby preventing their absorption by the body.
3. Barium Sulfate Precursor: Barium oxalate can be used as a precursor to produce barium sulfate (BaSO4), which is widely used as a contrast medium in X-ray imaging and other medical procedures.

Barium oxalate is toxic if ingested, inhaled, or absorbed through the skin, and it should be handled with care. It is essential to work with this compound in a well-ventilated area and use appropriate personal protective equipment to minimize exposure and potential risks.

As with any chemical, safety precautions should be taken when handling barium oxalate. Proper waste disposal procedures should also be followed to prevent environmental contamination.

It is important to note that the use of barium oxalate as an antidote for poisoning is not recommended, and its use for this purpose has been largely discontinued due to potential toxicity and the availability of more effective and safer treatments. If poisoning is suspected, it is essential to seek immediate medical attention from healthcare professionals.