Malachite green metabolized into LMG. Only the cation MG is deeply colored, whereas the leuco and alcohol derivatives are not. This difference arises because only the cationic form has extended pi-delocalization, which allows the molecule to absorb visible light. The leuco form of malachite green was first prepared by Hermann Fischer in 1877 by condensing benzaldehyde and dimethylaniline in the molecular ratio 1:2 in the presence of sulfuric acid. Malachite green is traditionally used as a dye. Kilotonnes of MG and related triarylmethane dyes are produced annually for this purpose. MG is active against the oomycete "Saprolegnia", which infects fish eggs in
Italian submarine Malachite in Cagliari, when already in view of the Sardinian coast she was spotted by the Dutch submarine HNLMS Dolfijn in the morning of February 9, 1943. At approximately 11:00, HNMS Dolfijn launched a salvo of 4 torpedoes at "Malachite". The Italian submarine managed to avoid three of them by deftly maneuvering, but the fourth one hit her on the stern, and she sank within a minute taking down 35 crew with her. Commander Cinti, three other officers, and nine NCOs and sailors managed to escape. The wreck of "Malachite" was located in September 1999 at a depth of 117 to