|
75. RheniumName: Rhenium
Rhenium is silvery white with a metallic lustre; its density is exceeded only by that of platinum, iridium, and osmium, and its melting point is exceeded only by that of tungsten and carbon. It has other useful properties. It is expensive but useful as a trace alloying agent. Rhenium (Latin Rhenus meaning "Rhine") was the last naturally-occurring element to be discovered. It is generally considered to be discovered by Walter Noddack, Ida Tacke, and Otto Berg in Germany. In 1925 they reported that they detected the element in platinum ore and in the mineral columbite. They also found rhenium in gadolinite and molybdenite. In 1928 they were able to extract 1 g of element by processing 660 kg of molybdenite. The process was so complicated and the cost so high that production was discontinued until early 1950 when tungsten-rhenium and molybdenum-rhenium alloys were prepared. These alloys found important applications in industry that resulted in a great demand for the rhenium produced from the molybdenite fraction of porphyry copper ores. Little is known about rhenium toxicity so it should be handled with care. Quick links
|