Science, Tech, Math › Science Interesting and Useful Facts about Iron Share Flipboard Email Print This is a photograph of various forms of high-purity elemental iron. Iron is a blue-gray metal found in steel and many other alloys as well as in pure form. Alchemist-hp / Wikimedia Commons / [FAL] Science Chemistry Periodic Table Basics Chemical Laws Molecules Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 07, 2019 Iron is one of the elements you encounter in its pure form. It is essential for nutrition and used in a variety of household objects. Here are some quick facts about iron. Iron Facts Iron is an element that has been known in its pure form for at least 5,000 years. The name "iron" comes from the Anglo-Saxon word "iron" and Scandinavian "iarn" for the metal.The element symbol for iron is Fe, which comes from the Latin word for iron, "ferrum."Iron is one of the most plentiful elements. It comprises about 5.6 percent of the Earth's crust and almost all of its core.The single largest use of iron is to make steel, an alloy of iron, and a smaller amount of carbon. According to archaeological records from Anatolia—also called Asia Minor, a peninsula that today makes up the Asian part of Turkey—man has been producing steel for at least 4,000 years.Iron is a transition metal.Iron is not always magnetic. The a allotrope (or form) of iron is ferromagnetic, yet if it is transformed to the b allotrope, the magnetism disappears even though the crystal lattice is unchanged.Animals and plants require iron. Plants use iron in chlorophyll, the pigment used in photosynthesis. Humans use iron in hemoglobin molecules in blood to allow for the transport of oxygen to tissues throughout the body.Although iron is an essential mineral, much of it is extremely toxic. Free iron in the blood reacts with peroxides to form free radicals that damage DNA, protein, lipids and other cellular components, leading to illness and sometimes death. Twenty milligrams of iron per kilogram of body weight is toxic, while 60 milligrams per kilogram is lethal.Iron primarily forms compounds with +2 and +3 oxidation states.Iron is formed via fusion in stars that have sufficient mass. The sun and many other stars contain significant amounts of iron.