mercuric sulfide

Mercuric sulfide (HgS) is an insoluble chemical compound that occurs naturally as the minerals cinnabar (red) and metacinnabar (black). It can also be synthesized in both red and black forms. Mercury itself is a unique chemical element, being the only metal liquid at room temperature.12

While mercury compounds have historically been used for medical purposes, their toxicity is a significant concern. Mercury poisoning can result from exposure to mercury vapors, dusts, or soluble salts, affecting various bodily systems, including the digestive tract and central nervous system. Due to its toxicity, the use of mercury has been phased out in many applications, such as thermometers and chlorine production.23