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Iron(II,III) oxide, or black iron oxide, is the chemical compound with formula Fe 3 O 4.It occurs in nature as the mineral magnetite.It is one of a number of iron oxides, the others being iron(II) oxide (FeO), which is rare, and iron(III) oxide (Fe 2 O 3) which also occurs naturally as the mineral hematite.
Magnetite is one of the very few minerals that is ferrimagnetic; it is attracted by a magnet as shown here. Unit cell of magnetite. The gray spheres are oxygen, green are divalent iron, blue are trivalent iron. Also shown are an iron atom in an octahedral space (light blue) and another in a tetrahedral space (gray).
New York: The International Nickel Company, Inc., 1941: 16. — "Values ranging from 21.3 to 21.5 gm/cm 3 at 20 °C have been reported for the density of annealed platinum; the best value being about 21.45 gm/cm 3 at 20 °C." 21.46 g/cm 3 — Rose, T. Kirke. The Precious Metals, Comprising Gold, Silver and Platinum.
Extensive properties. [edit] An extensive property is a physical quantity whose value is proportional to the size of the systemit describes,[8]or to the quantity of matter in the system. For example, the mass of a sample is an extensive quantity; it depends on the amount of substance. The related intensive quantity is the density which is ...
Mill scale, often shortened to just scale, is the flaky surface of hot rolled steel, consisting of the mixed iron oxides iron (II) oxide (FeO, wüstite), iron (III) oxide (Fe2O3, hematite), and iron (II,III) oxide (Fe3O4, magnetite). Mill scale is formed on the outer surfaces of plates, sheets or profiles when they are produced by passing red ...
statvolt (CGS unit) statV. ≘ c ⋅ (1 μJ/A⋅m) = 299.792458V. volt (SI unit) V. The difference in electric potential across two points along a conducting wire carrying one ampere of constant current when the power dissipated between the points equals one watt. [ 32 ] = 1 V = 1 W/A = 1 kg⋅m2/ (A⋅s3) = 1 J/C.
Some quantities are known as several different names such as the magnetic B-field which is known as the magnetic flux density, the magnetic induction or simply as the magnetic field depending on the context. Similarly, surface tension can be denoted by either σ, γ or T. The table usually lists only one name and symbol that is most commonly used.
The formula for magnetite is more accurately written as FeO·Fe 2 O 3 than as Fe 3 O 4. Magnetite is one part FeO and one part Fe 2 O 3, rather than a solid solution of wüstite and hematite. Magnetite is termed a redox buffer because, until all Fe 3+ present in the system is converted to Fe 2+, the oxide mineral assemblage of iron remains