538 MANGANESE. 



without contact of organic matter, and allowed to crystallize. 

 The crystals are of a dark purple colour, almost black, and soluble 

 in sixteen times their weight of cold water ; they were found by 

 Mitscherlich to be isomorphous with hyperchlorate of potash. 

 The hypermanganates give out oxygen when heated, and are 

 reconverted into manganates. Their solutions have a rich pur- 

 ple colour, and are so stable that they may be boiled, if con- 

 centrated. A small portion of a hypermanganate imparts a 

 purple colour to a very large quantity of water. 



The insoluble manganate of barytes may be formed by fusing 

 peroxide of manganese with nitrate of barytes ; and when mixed 

 with a little water, and decomposed by an equivalent quantity of 

 sulphuric acid, affords free bypermanganic acid. In Mitscher- 

 lich's experiments, the free acid appeared to be a body not 

 more stable than peroxide of hydrogen, being decomposed 

 between 86 and 104, with the escape of oxygen gas and pre- 

 cipitation of hydrated peroxide of manganese. It bleached 

 powerfully, and was rapidly destroyed by all kinds of organic 

 matter. M. Huenefeld, on the other hand, obtained hyper- 

 manganic acid in a state in which it could be preserved, evapo- 

 rated, redissolved, &c. He washed the manganate of barytes 

 with hot water, by which it is resolved into peroxide of man- 

 ganese and hypermanganate of potash, and then added to it the 

 quantity of phosphoric acid exactly necessary to neutralise the 

 barytes. The liberated hypermanganic acid was dissolved out, 

 evaporated to dryness, and by a second solution and evapora- 

 tion, obtained in the form of a reddish brown mass, crystalline 

 and radiated, which exhibited the lustre of indigo at some 

 points, and was entirely soluble in water. When dry hyper- 

 manganic acid was fused in a retort with anhydrous sulphuric 

 acid, and afterwards distilled by a higher temperature, an acicular 

 sublimate, of a crimson red colour was obtained, which appeared 

 to be a combination of hypermanganic and sulphuric acids. 

 (Berzelius's Traite, i. 522.) 



Hyperchloride of manganese, Mn 2 C1 7 , is a greenish yellow gas, 

 which condenses at zero into a liquid of a greenish brown 

 colour. This liquid diffuses purple fumes, owing to the forma- 

 tion of hydrochloric and hypermanganic acids, by the decom- 

 position of the moisture of the air. It was formed by Dumas 

 by dissolving the manganate of potash in oil of vitriol, pouring 



