Unlike the oxides of some other metals that form passivating layers, rust occupies more volume than the metal and thus flakes off, exposing more fresh surfaces for corrosion.

Iron reacts readily with oxygen and water to produce brown-to-black hydrated iron oxides, commonly known as rust. Pristine and smooth pure iron surfaces are a mirror-like silvery-gray. The iron and steel industry is thus very important economically, and iron is the cheapest metal, with a price of a few dollars per kilogram or pound. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechanical properties and low cost. That event is considered the transition from the Bronze Age to the Iron Age. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. It is the fourth most common element in the Earth's crust, being mainly deposited by meteorites in its metallic state.Įxtracting usable metal from iron ores requires kilns or furnaces capable of reaching 1,500 ☌ (2,730 ☏), about 500 ☌ (932 ☏) higher than that required to smelt copper. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core.

It is a metal that belongs to the first transition series and group 8 of the periodic table. Iron is a chemical element it has symbol Fe (from Latin ferrum 'iron') and atomic number 26.

Ion color chart permanent