|Atomic Symbol||Atomic symbol::Er|
|Atomic Number||Atomic number::68|
|Atomic Weight||Atomic weight::167.26 g/mol|
|Appearance|| soft & malleable metal w/ a bright silver luster |
|Group, Period, Block||N/A, 6, 4f|
|Electron configuration||[Xe] 6s2 4f12|
|Electrons per shell|| 2,8,18,30,8,2 |
|CAS number||CAS number::7440-52-0|
|Melting point||Melting point::1529°C|
|Boiling point||Boiling point::2868°C|
|Isotopes of Erbium|
|All properties are for STP unless otherwise stated.|
With an atomic symbol of Er, atomic number of 68, Lanthanide series element, Erbium is a rare-earth metal and can be pricey in its pure state. It was discovered in a mine near Ytterby Sweden; along with ytterbium, yttrium, and terbium in 1843 by Carl Gustaf Mosander. Erbium oxide is pink while the element itself is a silver color. Erbium the metal is used in lasers and optic fibers.
Erbium is a rare-earth metal with a silvery, metallic luster, which does not oxidize in the air like most others rare-earth metals. There are nine recognized radioactive isotopes of erbium; however, most erbium that is found is stable. It is a physical solid at room temperature with a density of 9.2 g/mL. Erbium also has a melting point of 1529°C and a boiling point of 2868°C.  The material, erbia, is erbium oxide (Er2O3) and has a pink color. Other erbium compounds includes: erbium fluoride (ErF3), erbium chloride (ErCl3) and erbium iodide (ErI3).Erbium has an oxidation number of +3 and a hexagonal close-packed structure . Though it is not known the effect erbium it has on humans, it seems best to assume that the element is toxic. 
This element is not found in nature by itself. Instead, it is found (though more abundantly) with other rare-earth elements. The main mining of erbium takes place in China and the US. The most important ores that erbium is found with are monazite and bastanite. Erbium has a 0.4 log of abundance in the earth's crust and costs $765 per 100g in it's pure form; $65 per 100g in bulk (mixed with other elements).  The world production of erbium per year is 500 tons.  Erbium ranks at 42 in the abundance in the earth’s crust, more common than bromine, uranium, tin, silver and mercury. It is also commonly found in the mixture of other lanthanide elements in xenotime, fergusonite, gadolinite, and euxenite. 
Since erbium is hardly ever found by its own, extrication is required. Erbium in a mineral is first converted into erbium fluoride (ErF 3 ). Pure erbium is then obtained by passing an electric current through erbium fluoride. Erbium the metal has few uses when compared to other elements like carbon or copper. 
Erbium can be combined with Vanadium, making it softer and more malleable. It is also used infrequently in nuclear power. Erbium oxide has a pink color, so it is used in coloring glasses and porcelain enamel glazes. It is also used in photographic filters. 
Erbium is used in erbium laser resurfacing. Resurfacing removes the top most layer of the epidermis, revealing the under lying layers of skin for a younger look. This removes superficial lines to moderately deep wrinkles with less pain, fewer side-effects, and more rapid recovery than other treatments. 
The most important use of Erbium is optic fibers. Optic fibers are thin thread-like pieces of glass or plastic through which light travels easily. Copper was originally used, but erbium was found to be more useful. Erbium optic fibers are still being used by military applications and in long distance communication systems. Erbium optic fibers are much better than copper wires such that telephone providers are converting all their old copper wires to optic fibers for better clarity. 
In 1843, a quarry in Ytterby, Sweden, un-earthed mineral gadolinite ((Ce, La, Nd, Y)2FeBe2Si2O10), an unusual black mineral found in the quarry by a Swedish army officer named Carl Axel Arrhenius . The Swedish chemist, Carl Gustaf Mosander, separated the gadolinite into three materials that he called yttria (yttirium oxide), erbia (erbium oxide) and terbia (terbium oxide). Due to the similarities in the names, future chemists confused the different elements of erbia and terbia for each other. By 1877, chemists had completely reversed the names. Mosander then discovered Erbium and Terbium from these two elements.   While Mosaunder was given credit for discovering erbium, he only saw the erbia, the mixture of erbium and an oxide. The erbia he saw wasn't pure erbia either, but a mixture of other rare-earth element oxides.
Erbium oxide’s first pure sample was produced in 1905 by French chemist George Urbain (1872-1938) and American chemist Charles James (1880-1928). However, it was not until 1934 that the first pure erbium metal was produced in Stockholm, Sweden.  
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