Malachite green colored cation. The oxalate salt is also marketed. The anions have no effect on the color. The intense green color of the cation results from a strong absorption band at 621 nm (extinction coefficient of ). Malachite green is prepared by the condensation of benzaldehyde and dimethylaniline to give leuco malachite green (LMG): Second, this colorless leuco compound, a relative of triphenylmethane, is oxidized to the cation that is MG: A typical oxidizing agent is manganese dioxide. Hydrolysis of MG gives an alcohol: This alcohol is important because it, not MG, traverses cell membranes. Once inside the cell, it is
Mineral a common formula of XY(Si,Al)O, where X and Y are both cations, with X typically bigger than Y; the pyroxenes are single-chain silicates that crystallize in either the orthorhombic or monoclinic crystal systems. Finally, a mineral variety is a specific type of mineral species that differs by some physical characteristic, such as colour or crystal habit. An example is amethyst, which is a purple variety of quartz. Two common classifications, Dana and Strunz, are used for minerals; both rely on composition, specifically with regards to important chemical groups, and structure. James Dwight Dana, a leading geologist of his time, first