Iron(III) oxide
From Freepedia
| Iron(III) oxide | |
|---|---|
| Image:Iron(III) oxide.jpg | |
| General | |
| Other names | Ferric oxide Hematite |
| Molecular formula | Fe2O3 |
| Molar mass | 159.69 g/mol |
| Appearance | red-brown solid |
| CAS number | [1317-60-8] |
| Properties | |
| Density and phase | 5.24 g/cm3, solid |
| Solubility in water | insoluble |
| Melting point | 1565 °C decomp. |
| Structure | |
| Coordination geometry | ? |
| Crystal structure | ? |
| Thermodynamic data | |
| Std enthalpy of formation ΔfH | −825.50 kJ/mol |
| Standard molar entropy S | 87 J·K−1·mol−1 |
| Hazards | |
| MSDS | External MSDS |
| EU classification | |
| R-phrases | |
| S-phrases | |
| Flash point | non-flammable |
| Supplementary data page | |
| Structure and properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | Iron(II) sulfide |
| Other cations | Iron(II) oxide Iron(II,III) oxide Ruthenium(IV) oxide Osmium(IV) oxide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Iron(III) oxide — also known as ferric oxide, red iron oxide, synthetic maghemite, colcothar, or simply rust — is one of several oxide compounds of iron, and is most notable for its ferromagnetic properties. Its chemical formula is Fe2O3.
The mineral form of ferric oxide is hematite; it is mined as the main ore of iron.
Iron(III) oxide is often used in magnetic storage, for example in the magnetic layer of floppy disks. These consist of a thin sheet of Mylar® plastic, coated with iron(III) oxide. The particles can be magnetised to represent binary data. MICR (Magnetic Ink Character Recognition) also uses iron(III) oxide compounds, suspended in an ink which can be read by special scanning hardware.
The majority of recorded information on earth (such as text and photographs) is stored in the form of magnetization patterns on a thin layer of iron(III) oxide. This is probably because the cost per bit of iron-based magnetic media is currently far less than the cost per bit of any known alternative, such as optical discs, paper books, or microfilm.
A very fine powder of ferric oxide is known as jeweller's rouge, red rouge, or simply rouge. It is used to put the final polish on metallic jewellery and lenses, and historically as a cosmetic.
Rouge cuts slower than some modern polishes, such as cerium(IV) oxide, but is still used in optics fabrication and by jewelers for the superior finish it can produce. When polishing gold, the rouge slightly stains the gold, which contributes to the appearance of the finished piece. Rouge is sold as a powder, paste, or solid bar (with a wax or grease binder). Other polishing compounds are also often called "rouge", even when they do not contain iron oxide.
Uses
Iron(III) Oxide is used in the production of pure iron in a blast furnace. Iron(III) Oxide is also part of an extremly exothermic reaction called a thermite reaction.
