From Academic Kids
|Name, Symbol, Number||Erbium, Er, 68|
|Group, Period, Block||NA, 6, f|
|Density, Hardness||9066 kg/m3, ND|
|Appearance|| silvery white|
|Atomic weight||167.259 amu|
|Atomic radius (calc.)||175 (226) pm|
|Covalent radius||ND pm|
|van der Waals radius||ND pm|
|e- 's per energy level||2,8,18,30,8,2|
|Oxidation states (Oxide)||3 (basic)|
|State of matter||solid|
|Melting point||1795 K (2772 ?F)|
|Boiling point||3136 K (5185 ?F)|
|Molar volume||ND ×10-6 m3/mol|
|Heat of vaporization||261 kJ/mol|
|Heat of fusion||17.2 kJ/mol|
|Velocity of sound||2830 m/s at 293.15 K|
|Electronegativity||1.24 (Pauling scale)|
|Specific heat capacity||170 J/(kg*K)|
|Electrical conductivity||1.17 106/m ohm|
|Thermal conductivity||14.3 W/(m*K)|
|1st ionization potential||589.3 kJ/mol|
|2nd ionization potential||1150 kJ/mol|
|3rd ionization potential||2194 kJ/mol|
|4th ionization potential||4120 kJ/mol|
|Most stable isotopes|
|SI units & STP are used except where noted.|
Erbium is a chemical element in the periodic table that has the symbol Er and atomic number 68. A rare silvery metallic lanthanide rare earth element, erbium is associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden.
A trivalent element, pure erbium metal is malleable, soft, somewhat stable in air and does not oxidize as quickly as some other rare-earth metals. Its salts are rose-colored and the element gives a characteristic sharp absorption spectra in visible light, ultraviolet, and near infrared. Otherwise it looks much like the other rare earths. Its sesquioxide is called erbia. Erbium's properties are to a degree dictated by the kind and amount of impurities present. Erbium does not play any known biological role but is thought by some to be able to stimulate metabolism.
Erbium's everyday uses are varied; commonly it is used as a photographic filter and because of its resilience it is useful as an metallurgical additive. Other uses:
- Used in nuclear technology as a neutron absorber.
- Used as a dopant in Fiber amplifiers.
- When added to vanadium as an alloy erbium lowers hardness and improves workability.
- Erbium oxide has a pink color and is therefore sometimes used as a glass and porcelain enamel glaze colorant. The glass is then often used in sunglasses and cheap jewelry.
Erbium (for Ytterby, a town in Sweden) was discovered by Carl Gustaf Mosander in 1843. Mosander separated "yttria" from the mineral gadolinite into three fractions which he called yttria, erbia, and terbia. He named the new element after the town of Ytterby where large concentrations of yttria and erbium are located. Erbia and terbia, however, were confused in at this time. After 1860, what had been known as terbia was renamed erbia and after 1877 what had been known as erbia was renamed terbia. Fairly pure Er2O3 was independently isolated in 1905 by Georges Urbain and Charles James. Reasonably pure metal wasn't produced until 1934 when workers reduced the anhydrous chloride with potassium vapor.
Like other rare earths, this element is never found as a free element in nature but is found bound monazite sand ores. It has historically been very difficult and expensive to separate rare earths from each other in their ores but ion-exchange production techniques developed in the late 20th century have greatly brought down the cost of production of all rare-earth metals and their chemical compounds. The principal commercial sources of erbium are from the minerals xenotime and euxenite. Metallic erbium in dust form presents a fire and explosion hazard.
Naturally occurring erbium is composed of 6 stable isotopes, Er-162, Er-164, Er-166, Er-167, Er-168, and Er-170 with Er-166 being the most abundant (33.6% natural abundance). 23 radioisotopes have been characterized, with the most stable being Er-169 with a half life of 9.4 days, Er-172 with a half-life of 49.3 hours, Er-160 with a half-life of 28.58 hours, Er-165 with a half-life of 10.36 hours, and Er-171 with a half life of 7.516 hours. All of the remaining radioactive isotopes have half-lifes that are less than 3.5 hours, and the majority of these have half lifes that are less than 4 minutes. This element also has 6 meta states, with the most stable being Er-167m (t? 2.269 seconds).
The isotopes of erbium range in atomic weight from 144.957 amu (Er-145) to 173.944 amu (Er-174). The primary decay mode before the most abundant stable isotope, Er-166, is electron capture, and the primary mode after is beta decay. The primary decay products before Er-166 are element 67 (holmium) isotopes, and the primary products after are element 69 (thulium) isotopes.
As with the other lanthanides, erbium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail.
- Los Alamos National Laboratory – Erbium (http://periodic.lanl.gov/elements/68.html)
- Guide to the Elements – Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1
- It's Elemental – Erbium (http://education.jlab.org/itselemental/ele068.html)