Mercury sulfide Mercury sulfide Mercury sulfide, mercuric sulfide, mercury sulphide, or mercury(II) sulfide is a chemical compound composed of the chemical elements mercury and sulfur. It is represented by the chemical formula HgS. It is virtually insoluble in water. HgS is dimorphic with two crystal forms: Crystals of red, α-HgS, are optically active. This is caused by the Hg-S helices in the structure. β-HgS is precipitated as a black powder when HS is bubbled through solutions of Hg(II) salts. β-HgS is unreactive to all but concentrated acids. Mercury metal is produced from the cinnabar ore by roasting in air and condensing the
Cinnabar moth eggs. The larvae absorb toxic and bitter tasting alkaloid substances from the foodplants, and assimilate them, becoming unpalatable themselves. The bright colours of both the larvae and the moths act as warning signs, so they are seldom eaten by predators. An exception is among different species of Cuckoo which eat hairy and poisonous caterpillars including cinnabar moth larvae. Females can lay up to 300 eggs, usually in batches of 30 to 60 on the underside of ragwort leaves. When the caterpillars (larvae) hatch they feed on and around the area of the hatched eggs but as they get bigger and