It is a colorless liquid. It evaporates very fast. It is a very strong toxin to the nervous system. It doesn't react with water like other similar chemicals. It contains mercury in its +2 oxidation state. It can react with mercury(II) chloride to make a crystalline chemical compound.
It has almost no uses. It is rarely used to test instruments that are used to detect mercury.
It is extremely toxic. If just a drip gets placed on human skin, it will poison the person. It gets into the brain easily when it goes through the skin. The poisoning does not happen quickly, though. It sometimes can take months before the poisoning effects show.