Cinnabar Cinnabar Cinnabar () and cinnabarite (), likely deriving from the ("kinnabari"), refer to the common bright scarlet to brick-red form of mercury(II) sulfide (HgS) that is the most common source ore for refining elemental mercury, and is the historic source for the brilliant red or scarlet pigment termed vermilion and associated red mercury pigments. Cinnabar generally occurs as a vein-filling mineral associated with recent volcanic activity and alkaline hot springs. The mineral resembles quartz in symmetry and in its exhibiting birefringence; cinnabar has a mean refractive index of approximately 3.2, a hardness between 2.0 and 2.5, and a specific gravity
Metal ammine complex is ammonia (pK ~ 33). For highly cationic complexes such as [Pt(NH)], the conjugate base can be obtained. The deprotonation of cobalt(III) ammine-halide complexes, e.g. [CoCl(NH)] labilises the Co-Cl bond, according to the Sn1CB mechanism. Metal ammine complexes find many uses. Cisplatin (PtCl(NH)) is a coordination compound containing two chloro and two ammine ligands. This is a drug used in treating cancer. Many other amine complexes of the platinum group metals have been evaluated for this application. In the separation of the individual platinum metals from their ore, several schemes rely on the precipitation of [RhCl(NH)]Cl. In some separation schemes,