Pendant. Manganese.

<div>   </div> <div> <strong> Atomic number <span class = "Apple-tab-span" style = "white-space: pre;"> </span>       25 </strong> </div> <div> <strong> Atomic mass <span class = "Apple-tab-span" style = "white-space: pre;"> </span>       54,938 </strong> </div> <div> <strong> Density, kg / m? <Span class = "Apple-tab-span" style = "white-space: pre;"> </span>     7430 </strong> </div> <div> <strong> Temperature </strong></div> <div> <strong> melting, ° С <span class = "Apple-tab-span" style = "white- space: pre; "> </span>         1244 </strong> </div> <div>   </div> <div> Manganese is a hard, brittle metal with a silvery white color. Along with iron and its alloys, it belongs to ferrous metals. </div> <div> Manganese minerals have been known for a long time. The ancient Roman naturalist Pliny mentions a black stone that was used to discolor a liquid glass mass; it was about the mineral pyrolusite. Since ancient times, pyrolusite has served as a filler material in the production of iron in Georgia. For a long time, pyrolusite was called black magnesia and was considered a type of magnetic iron ore (magnetite). In 1774, K. Scheele showed that this is a compound of an unknown metal, and another Swedish scientist, Yu. Gan, strongly heating a mixture of pyrolusite with coal, and obtained manganese contaminated with carbon. The name Manganese is traditionally derived from the German Manganerz - manganese ore. </div>