Iron Definition and 517 Threads

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.

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  1. B

    Calculating Torque of a String Attached to an Iron Bar

    There is a 0.8m long, 1.2 iron bar with a string attached to the center, making a 35 degree angle (from the bar). Calculate the torque produced by the tension in the string. A pivot at one end holds the bar, and the string is attached at the bar's center, which is the center of mass. I'm...
  2. T

    Calculating PPM Iron: Iron Titration

    Please Help! I have no idea where to start with this one! A 100.0mL sample of water was treated to convert any iron present to ferrous ion. Addition of 25mL of 0.002107M potassium dichromate converted the iron to ferric ion and the dichromate to Cr3+. Excess dichromate was then back...
  3. D

    Nd2Fe14B: Molecular Structure Explained

    Does anyone know how does this molecule looks like? (I study Aerospace, don't ask me why do i want to know :cry: ) How does those atomos connect with each other: It's chemical formulae is: Nd_2Fe_1_4B
  4. H

    What is the volume of an iron atom?

    Plz help ASAP! Iron has a mass of 7.87g/cm^3 of volume, and the mass of an iron atom is 9.27x10^(-26)kg. If the atoms are spherical and tightly packed, a) a) what is the volume of an iron atom? --> this one I do know how to do it, the answer is 1.18x10^29 m^3 b) what is the distance between...
  5. J

    Calculating Temperature Increase in Iron with Double the Molecules

    For most of you experts out there, this should be fairly simple to answer. Well, technically, all it takes is logic to answer this: A block of Iron has a temperature of 10 degrees celsius. There is a second block of iron, identicle to the first, that is 2x the temperature of the first block...
  6. C

    Find the length of the side of a cube of iron

    Iron has a property such that a 1.00m^3 volume has a mass of 7.86 X 10^3kg(density equals 7.86 X 10^3kg/m^3). You want to manufacture iron into cubes and spheres. 1.) Find the length of the side of a cube of iron that has a mass of 480 g. 2.) Find the radius of a solid sphere of iron...
  7. T

    Exploring the Iron Rusting Reaction with KMnO4

    Hi everyone, I'm not sure what would happen in the following reaction (it has something to do with the rusting of iron): Fe (s) + KMnO4 (aq) ----> ? KMnO4 is potassium permanganate and I know it is a very strong oxidizer. So I am assuming one of the products may be Fe2O3, which is...
  8. Q

    Why Does All Matter in the Universe Want to Become Iron?

    I am currently reading "In Search of Schrodenger's Cat" by John Gribbon. In the book he refers to iron as the most desirable form of matter and that all the matter in the universe "wants" to become iron. I think I recall a professor describing the collapse of a star under gravity and the...
  9. S

    How does a permanent magnet lift iron filings

    Evryone knows that the work done by a magnetic field is zero. Then how does a permanent magnet lift iron filings.
  10. S

    How does the magnetic field lift iron objects?

    We all know that the work done by the magetic field is zero. But, how does the magnetic field lift iron objects?
  11. Ivan Seeking

    The Iron Dragon and a day of time travel.

    "The Iron Dragon" and a day of time travel. Last weekend Tsunami and I met my parents for a very unusual weekend that begins in the hidden mountain town of McCloud; right next to the majestic, silently sleeping, snow covered volcano called Mount Shasta, in Northern California. The day begins at...
  12. D

    IS there an iron core in our sun?

    Has anyone seen the hypothesis of http://web.umr.edu/~om/ regarding the possibility our sun is the result of a re-accretion on a supernova remnant? I looked but haven't seen anything on it in the forum, and was wondering what you'all think if it? :confused:
  13. F

    The Iron inside a cell pulls and holds on to the oxygen

    Now for another question on the same subject You all know how in the human body the oxygen binds to the iron compound inside the hemoglobin. and that carbon monoxide has a 200 to 1 affinity to oxygen within the hemoglobin. But anyway my question is if The Iron inside a cell pulls and holds on...
  14. iansmith

    Iron-Eating Bacteria Clean Up Contaminated Environments - By Cathy Holding

    http://www.biomedcentral.com/news/20040226/01
  15. A

    Cooling Iron/Steel: Durability, Hardness and Structure

    I am considering getting into forging metal things at home as a hobby. Setting up a little smithy in the back. I thought I'd try making some blades and such. What are the properties of iron/steel as it cools? At what rate should it be cooled for different hardness or durability? What...
  16. A

    Iron Fusion in Stars: Uncovering the Mysteries of Heavy Elements on Earth

    [SOLVED] Iron Fusion In Stars If iron is said to be the last stage of fusion in stars, how is it that heavier elements are found on earth, where there seems to be less likely a chance for such fusion to occur? Where do these elements come from? Moreover, the half-life of a heavy element on...
  17. Tyger

    Testing Magnetic Properties of Iron Crystals without Damage

    Was going to put this up a couple of days ago but was a bit preoccupied. So here goes. Imagine that you take a single crystal of Iron, a whisker, and bend it around to make a circle. How could you find out if the crystal was magnetized? Remember, all the magnetic field is contained inside the...
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