![red mercuric sulfide red mercuric sulfide](https://www.tekportal.net/wp-content/uploads/2018/11/red-mercuric-sulfide.jpg)
noun
- See under mercuric sulfide.
noun Chemistry.
- a crystalline, water-insoluble, poisonous compound, HgS, occurring as a coarse, black powder (black mercuric sulfide) or as a fine, bright-scarlet powder (red mercuric sulfide): used chiefly as a pigment and as a source of the free metal.