Cinnabar

related topics
{acid, form, water}
{@card@, make, design}
{language, word, form}
{church, century, christian}
{island, water, area}
{build, building, house}
{black, white, people}
{food, make, wine}

Cinnabar, or cinnabarite (red mercury(II) sulfide (HgS), native vermilion), is the common ore of mercury. The name comes from κινναβαρι (kinnabari), a Greek word most likely applied by Theophrastus to several distinct substances. Other sources say the word comes from the Persian شنگرف shangarf (زینجیفرح zinjifrah, a word of uncertain origin). In Latin it was sometimes known as minium, meaning also "red lead", though both of these terms now refer specifically to lead tetroxide.

Contents

Structure

HgS adopts two structures, i.e. it is dimorphous.[5] The more stable form is cinnabar, which has a structure akin to that for HgO: each Hg center has two short Hg-S bonds (2.36 Å), and four longer Hg---S contacts (3.10, 3.10, 3.30, 3.30 Å). The black form of HgS has the zinc blende structure.

Properties

Cinnabar is generally found in a massive, granular or earthy form and is bright scarlet to brick-red in color.[6] It occasionally occurs, however, in crystals with a non-metallic adamantine luster. Cinnabar has a rhombohedral bravais lattice, and belongs to the hexagonal crystal system, trigonal division. Its crystals grow usually in a massive habit, though they are sometimes twinned. The twinning in cinnabar is distinctive and forms a penetration twin that is ridged with six ridges surrounding the point of a pyramid. It could be thought of as two scalahedral crystals grown together with one crystal going the opposite way of the other crystal. The hardness of cinnabar is 2–2.5, and its specific gravity 8.1.

Cinnabar resembles quartz in its symmetry and certain of its optical characteristics. Like quartz, it exhibits birefringence. It has the highest refractive power of any mineral. Its mean index for sodium light is 3.08,[7] whereas the index for diamond—a substance of remarkable refraction— is 2.42 and that for gallium (III) arsenide (GaAs) is 3.93.

Full article ▸

related documents
Biotite
Chemical reaction
Silicate
Synthetic element
Organic compound
Messenger RNA
Butane
Hexose
Aqueous solution
Metabolic pathway
Flavin
Synthetic radioisotope
Plasmolysis
Plagioclase
DNA ligase
Actinoid
Strong acid
Fermium
Radiogenic
Alkaline earth metal
Millerite
Aldehyde
SH3 domain
Amyl alcohol
Polyvinylpyrrolidone
Coordinate covalent bond
Vesicle (biology)
Stereoisomerism
Macromolecule
Serine