Iron Definition and 18 Discussions

Iron () is a chemical element with symbol Fe (from Latin: ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in front of oxygen (32.1% and 30.1%, respectively), forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust.
In its metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching 1,500 °C (2,730 °F) or higher, about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia by about 2000 BCE, and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels are by far the most common industrial metals, because of their mechanical properties and low cost.
Pristine and smooth pure iron surfaces are mirror-like silvery-gray. However, iron reacts readily with oxygen and water to give brown to black hydrated iron oxides, commonly known as rust. Unlike the oxides of some other metals, that form passivating layers, rust occupies more volume than the metal and thus flakes off, exposing fresh surfaces for corrosion. Although iron readily reacts, high purity iron, called electrolytic iron, has better corrosion resistance.
The body of an adult human contains about 4 grams (0.005% body weight) of iron, mostly in hemoglobin and myoglobin. These two proteins play essential roles in vertebrate metabolism, respectively oxygen transport by blood and oxygen storage in muscles. To maintain the necessary levels, human iron metabolism requires a minimum of iron in the diet. Iron is also the metal at the active site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants and animals.Chemically, the most common oxidation states of iron are iron(II) and iron(III). Iron shares many properties of other transition metals, including the other group 8 elements, ruthenium and osmium. Iron forms compounds in a wide range of oxidation states, −2 to +7. Iron also forms many coordination compounds; some of them, such as ferrocene, ferrioxalate, and Prussian blue, have substantial industrial, medical, or research applications.

View More On
  1. C

    Is it possible to build a low-voltage Thompson jumping ring apparatus?

    Hi all, I'm attempting to build a jumping ring apparatus (a core of iron with the bottom wrapped with wiring like an electromagnet, so that when a metal ring is placed on top of the coil and a current is run through the coil, the ring jumps up into the air). Looking on the internet, I'm seeing a...
  2. L

    An iron cylinder inside a solenoid

    From ##\oint_{\Gamma}\vec{H}\cdot d\vec{l}=\sum I## by Ampere's Law which gives ##H \Delta l=\Delta N\cdot i\Leftrightarrow H=n i## where ##n=## number of turns per unit length so ##i=\frac{H}{n}=\frac{10^3 A / m}{\frac{200}{0.2m}}=1 A##. Since ##\vec{H}=\frac{\vec{B}-\mu_0\vec{M}}{\mu_0}## we...
  3. Elementrist

    B Magnetic force driving a small iron ball

    How can I calculate the force from magnetic field of a solenoid, grabbing a small iron ball? I want to use the good old simple F=ma formula in order to calculate the ball's acceleration. But can't find a formula to somehow convert the known field quality (in unit Tesla) to Force (in unit...
  4. G

    A Image method with iron

    Hello, I am wondering if it is possible to calculate the B-field of a conductor above an iron plate just using the complex image method. To keep it simple let’s consider a 2D calculation, the metal plate is infinitely deep and wide and the conductor is infinitely long and thin. If the metal...
  5. sekushi0range

    Reason for Ferroin's color shift

    Ferroin is a redox indicator. It is the complexation of phenanthroline and iron. In its reduced state the Fe (II) - phenanthroline complex is red and in its oxidized state the Fe(III)- phenanthroline complex is blue. I am trying to understand in the context of d-d orbital transitions why this is...
  6. G

    Does an iron ring shield a static magnetic field?

    Hi. This picture shows an iron ring shielding a static magnetic field: Does this really work, and why? I know that a conductor can shield an electric field (Faraday cage) and a changing magnetic field (Lenz's law), but why would it shield a static field? Especially since iron is a ferromagnet.
  7. C

    Electrons, magnetism and spin

    Theory explains magnetism in iron as a combined effect of magnetic moments of electrons. Now, what is confusing me is that valence electrons in iron are supposed to be free. The valence band and conduction band overlap. So, what kind of orbital and spin-ular momentum do these free electrons...
  8. L

    Color of Fe(II) complexes

    There is something that I am not understanding about the visible colors of coordination complexes. I did a lab where I prepared [Fe(NH2trz)3]Br2 from FeBr2. Fe(NH2trz)3 was a violet color and FeBr2 was red. My understanding of colors in coordination complexes is that reds are high energy...
  9. Shahsquatch

    Magnet Fundamentals and Iron Powder

    I am creating a product that incorporates magnetic sensing of magnetic nanoparticles. However due to their cost, I have decided to search for other avenues of testing. My question is about whether Iron Powder will retain a magnetic field once magnetized. I basically will place some iron powder...
  10. G

    Zinc+Iron+Acetone+Hydrogen Peroxide

    When I added a zinc plated iron ball into the acetone-peroxide solution, they zinc started bubbling. The solution turned whitish. Then after leaving overnight it became grayish with orange red foam on top
  11. moenste

    Average mass of iron worn off the ring per day

    Homework Statement When iron is irradiated with neutrons an isotope of iron is formed. This isotope is radioactive with a half-value period (half-life) of 45 days. Give the meanings of the terms printed in italics. A steel piston ring of mass 16 g was irradiated with neutrons until its...
  12. H

    Oxidation of iron and galvanised iron in bleach

    In a laboratory experiment I have tested plain carbon steel in a beaker of bleach (sodium hypochlorite), immersed for a week. The result is a magenta-coloured solution with a large amount of ferrous hydroxide deposits. Q1) I haven't been able to find anywhere anything that might be causing...
  13. Arkthanon

    The Magnetic Force on an Iron Ring

    I decided to simulate this scene in Lord of the Rings for a project in school with the purpose of calculating the "real" mass of the One Ring. I've done the experiments according to this principle sketch but I have some troubles with calculating the magnetic force that the copper coil is...
  14. 1

    Which species of Fe are considered dissolved Fe?

    Homework Statement The question tells me that all dissolved iron species will have an activity of 0.1M. So is Fe(OH)42- considered a dissolved species of Fe, and if so, it will have an activity of 0.1M? Homework Equations N/A The Attempt at a Solution I want to say that it is not considered...
  15. Z

    Vaporization and Energy absorption

    In modern nanotechnologies, metals can be vapourized to coat onto the surface of another material as a thin but hard protective layer. How much energy would it take to heat 0.55 kg of iron from 1400oC to vapour at 2050oC?
  16. Stephanus

    Lithium fission

    Dear PF Forum, In previous thread, I am asking about fusion power. But there is one thing that intriguing me. This is one of the reactions that produces tritium. n + _3^6Li -> _2^4He + _1^3H + 4.8 Mev What is this reaction called? 1. Fusion? If yes, why it's called fusion? 2. Fission? 3. Other...
  17. R

    Magnetic powder question

    Does any kind of magnetic powder exist? I mean not iron powder, that is attracted to a magnet but vice versa, a type of powder, that when i take an iron nail or screw and get it close to that powder, the powder will attach itself to that iron object and stay there, for as long as it is not taken...
  18. R

    Ferromagnetic powder question!

    Hello! I am trying to understand a few properties of the ferromagnetic powder. I could not get the answers to these questions on the web, since any kind of phrasing i used, popped up search results that related to iron powder or ferromagnetic powder, which are manipulated and shape-shift...