July 6, 2022

Iron is the chemical element with atomic number 26. Its symbol is Fe, which originates from ferrum, the Latin name for this metallic element. It is the first element of group 8 of the periodic system, belonging to block d, and is therefore a transition element. Chemically pure iron under ambient conditions is a relatively soft, ductile and malleable metal, and chemically rather reactive. Below 768 ° C, Curie point, it exhibits ferromagnetism (hence the name), which is more intense than that of cobalt and nickel, which are the next elements in the periodic table. A sample of freshly abraded pure iron has a silver-gray sheen, which however is slowly lost in the air, due to the action of oxygen and humidity, and the surface is then covered with an incoherent patina, known as rust; this consists of mixed oxides and oxide-hydroxides (including FeOOH). Rust, however, does not protect the underlying metal from further corrosion, with the consequent considerable economic impact, which we have tried to quantify.This element is almost always found linked to others such as: carbon, silicon, manganese, chromium, nickel, etc. . With carbon, iron forms its two best known alloys: steel and cast iron. The word "iron" is incorrectly used in common parlance to also indicate low strength "iron alloys", mild steels. On an industrial level it is possible to obtain iron with a purity that is close to 100%. This product is then used to be bonded to other chemical elements to obtain alloys with the most diverse characteristics. Extremely important in technology for its mechanical characteristics and its workability, in the past it was so important that it gave its name to an entire historical period: the Iron Age.


Iron is formed by stellar Nucleosynthesis inside large-mass stars.


The first evidence of the use of iron comes from the Sumerians and the Hittites, who already used it for 4000 years BC for small objects such as spearheads and jewels made from iron recovered from meteorites. During the Middle Ages, iron was associated with Mars in alchemy. The history of the use and production of iron is common to that of its carbon alloys: cast iron and steel.


Scholars have estimated that iron is the most abundant metal inside the Earth, as it is present in large quantities in the Earth's core and mantle, along with nickel and sulfur. Limited to the earth's crust, iron, on the other hand, is the fourth most abundant element with a weight percentage of approximately 6.3%, preceded by oxygen (46%), silicon (27%) and aluminum (8.1%) , while it is estimated that it is the sixth element by abundance in the entire universe (with a percentage by weight of about 0.11%), preceded by hydrogen (75%), helium (23%), oxygen (1%), carbon (0.5%) and neon (0.13%). However, the large amount of iron present in the center of the Earth cannot be the cause of the geomagnetic field, since this element is in all likelihood at a temperature higher than the Curie temperature beyond which there is no magnetic ordering in the crystal lattice. Iron is a metal that is extracted from its minerals, consisting of chemical compounds of the iron itself, mainly oxides. In fact, iron is almost never found on the earth's crust in the elementary metallic state (native iron), but almost entirely in the form of compounds in which it is present in the oxidized state. To obtain metallic iron it is necessary to carry out a chemical reduction of its minerals. Iron is usually used to make steel which is an alloy based on iron, carbon and other elements. The most abundant nuclide of iron, 56Fe, has the smallest mass (930.412 MeV / c2) per nucleon, but it is not the most strongly bound nuclide.