holmium – erbium – thulium Er Fm       Full table
General
Name, Symbol, Number	Erbium, Er, 68
Chemical series	Lanthanides
Group, Period, Block	NA, 6 , f
Density, Hardness	9066 kg/m3, ND
Appearance	silvery white
Atomic properties
Atomic weight	167.259 amu
Atomic radius (calc.)	175 (226) pm
Covalent radius	ND pm
van der Waals radius	ND pm
Electron configuration	[Xe]6s²4f12
e- 's per energy level	2,8,18,30,8,2
Oxidation states (Oxide)	3 (basique)
Crystal structure	Hexagonal
Physical properties
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
Vapor pressure	ND
Velocity of sound	2830 m/s at 293.15 K
Miscellaneous
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
iso NA half-life DM DE MeV DP 160Er {syn.} 28.58 h ε 0.330 160Ho 162Er 0.14% Erbium is stable with 94 neutrons 164Er 1.61% Erbium is stable with 96 neutrons 165Er {syn.} 10.36 h ε 0.376 165Ho 166Er 33.6% Erbium is stable with 98 neutrons 167Er 22.95% Erbium is stable with 99 neutrons 168Er 26.8% Erbium is stable with 100 neutrons 169Er {syn.} 9.4 d β- 0.351 169Tm 170Er 14.9% Erbium is stable with 102 neutrons 171Er {syn.} 7.516 h β- 1.490 171Tm 172Er {syn.} 49.3 h β- 0.891 172Tm
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.

Contents

1 Notable characteristics 2 Applications 3 History 4 Occurrence 5 Isotopes 6 Precautions 7 References 8 External links

Notable characteristics

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 pretty much like the other rare earths. Its sesquioxide is called erbia. Erbium's properties are a 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.

Applications

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.

History

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.

Occurrence

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 principle commercial sources of erbium are from the minerals xenotime and euxenite. Metallic erbium in dust form presents a fire and explosion hazard.

Isotopes

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_½ 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.

Precautions

As with the other lanthanides, erbium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail.

References

• 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)

External links

• WebElements.com – Erbium (http://www.webelements.com/webelements/elements/text/Er/index.html) (also used as a reference)
• EnvironmentalChemistry.com – Erbium (http://environmentalchemistry.com/yogi/periodic/Er.html) (also used as a reference)
• High-res. pictures and details about erbium metal (http://www.seltenerden.de?arg=zoom&art=40&element=Er&linkid=ewiki-Er) (German)

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