Cadmium

Discovered by : Friedrich Stromeyer

Discovered in year : 1817

Cadmium is a rare metallic element. It is found in small deposits on almost every continent. Pure cadmium is rare in nature, it is usually found in combinations with other elements, typically copper, zinc, and lead. Cadmium is extracted from these ores during the smelting process or with the assistance of chemicals such as sulphuric acid. When isolated, cadmium is a soft, bluish white metal which is highly ductile, making it extremely suitable for metal alloys. It is named after the greek god 'Cadmus'. The element's atomic number is 48, and it is identified on the periodic table of elements with the symbol Cd, among the transition metals. Cadmium is toxic therefore it's usage is decreasing apart from it being used in nickel-cadmium batteries.

History - Cadmium was discovered a chemist named - Friedrich Stromeyer in Germany during  the year 1817. Stromeyer found the new element as an impurity in zinc carbonate (calamine). Stromeyer noted that some impure samples of calamine changed colour when heated but pure calamine did not. He was persistent in studying these results and eventually isolated cadmium metal by roasting and reduction of the sulfide. After it's discovery Germany remained the only important producer of the metal for 100 years.

Development of the discovery of Cadmium

In the 1930s and 1940s the industrial scale production of cadmium started in other countries. It's major application was the coating of steel and copper alloys to prevent corrosion.

During the 1950's, cadmium was being used to create yellow, orange, and red pigments based on sulfides and selenides of cadmium. It was used as a colouring agent.

In the 1970s and 1980s, it was started to be used as a stabilising agent in plastics as cadmium contained stabilizing chemicals on plastics. It  led to an increased use of those compounds. However at the same time, the usage of cadmium in all applications decreased as a result of environmental concerns and health regulations.

The overall consumption of cadmium has decreased by more than 10 times from the 1970s till 2009. Today it is highly in demand for it's use in nickel-cadmium batteries

Role of  Cadmium in the improvement of human life

• As a newly discovered element it found it's usage as anti-corrosive substance
• It is still widely used in rechargeable batteries which are very popular amongst audio-video equipments
• It also formed a capital generating industry involved in it's production