68
  Er  
167.260000
Erbium

Name: Erbium
Symbol: Er
Atomic Number: 68
Atomic Weight: 167.260000
Family: Rare Earth Elements
CAS RN: 7440-52-0
Description: A soft silvery white rare earth metal.
State (25C): Solid
Oxidation states: +3

Molar Volume: 18.45 cm3/mole
Valence Electrons: 4f126s2

Boiling Point:  3136K, 2863C, 5185F
Melting Point:
1795K, 1522C, 2772F
Electrons Energy Level: 2, 8, 18, 30, 8, 2
Isotopes: 29 + 6 Stable + 3 meta states
Heat of Vaporization:  261 kJ/mol
Heat of Fusion: 19.9 kJ/mol
Density:  9.07g/cm3 @ 300K
Specific Heat:  0.17 J/gK
Atomic Radius: 2.45
Ionic Radius: 0.881
Electronegativity: 1.24 (Pauling); 1.14 (Allrod Rochow)
57
La
138.9
58
Ce
140.1
59
Pr
140.9
60
Nd
144.2
61
Pm
(145)
62
Sm
150.4
63
Eu
152.0
64
Gd
157.3
65
Tb
158.9
66
Dy
162.5
67
Ho
164.9
68
Er
167.3
69
Tm
168.9
70
Yb
173.0
71
Lu
175.0

1s2 2s2p6 3s2p6d10 4s2p6d10f12 5s2p6 6s2

History

The mineral gadolinite, (Ce, La, Nd, Y)2FeBe2Si2O10, discovered in a quarry near the town of Ytterby, Sweden, has been the source of a great number of rare earth elements.  In 1843, Carl Gustaf Mosander, a Swedish chemist, was able to separate gadolinite into three materials, which he named yttria, erbia and terbia.   As might be expected considering the similarities between their names and properties, scientists soon confused erbia and terbia.   After 1860, terbia was renamed erbia and after 1877 what had been known as erbia was renamed terbia.  What Mosander called erbia is now called terbia and visa versa.  From these two substances, Mosander discovered two new elements, terbium and erbium. 

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 anydrous chloride with potassium vapor.   Today, erbium is primarily obtained through an ion exchange process from the minerals xenotime, YPO4, and euxenite, (Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)2O6.

Characteristics

A trivalent element, pure erbium metal is malleable (or easily shaped), soft yet 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, ultravolet, and near infrared.  Otherwise it looks much like the other rare earths.  Its sesquoxide 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 doped glasses or crystals can be used as optical amplification media, where erbium ions are optically pumped at around 980nm or 1480nm and then radiate light at 1550nm. This process can be used to create lasers and optical amplifiers.  The 1550nm wavelength is especially important for optical communications because standard single mode optical fibers have minimal loss at this particular wavelength.

1s2
2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f12
5s2 5p6
6s2

Occurrence

Like other rare earths, this element is never found as a free element in nature but is found bound in 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.

Applications

Erbium's everyday uses are varied.  It is commonly used as a photographic filter and because of its resilience it is useful as a metallurgical additive. Other uses:

Erbium is alloyed with vanadium to make it softer and easier to shape.  Erbium also has some uses in the nuclear power industry.

Compounds

Erbia, the renamed material that Mosander discovered in 1843, is erbium oxide (Er2O3), one of erbium's compounds.  Erbia has a pink color and is used to color glass and glazes.  Other erbium compounds include: erbium fluoride (ErF3, erbium chloride (ErCl3 and erbium iodide (ErI3).

Isotopes

Naturally occurring erbium is composed of 6 stable isotopes162Er, 164Er, 166Er, 167Er, 168Er, and 170Er with 166Er being the most abundant (33.6% natural abundance).  29 radioisotopes have been characterized, with the most stable being 169Er with a half life of 9.4 days, 172Er with a half-life of 49.3 hours, 160Er with a half-life of 28.58 hours, 165Er with a half-life of 10.36 hours, and 171Er 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 167mEr (t 2.269 seconds).

The isotopes of erbium range in atomic weight from 142.96634 amu (143Er) to 176.95405 amu (177Er).  The primary decay mode before the most abundant stable isotope, 166Er, is electron capture, and the primary mode after is beta decay.  The primary decay products before 166Er are element 67 (holmium) isotopes, and the primary products after are element 69 (thulium) isotopes.

atom.gif (700 bytes)

Isotope  
Atomic Mass
 
Half-Life
143Er 142.96634 ~200 ms
144Er 143.96038 ~400 ms
145Er 144.95739 900 ms
146Er 145.95200 1.7 seconds
147Er 146.94949 ~2.5 seconds
147mEr   2.5 seconds
148Er 147.94455 4.6 seconds
149Er 148.94231 4 seconds
149m1Er   8.9 seconds
150Er 149.937914 18.5 seconds
151Er 150.937449 23.5 seconds
152Er 151.935050 10.3 seconds
153Er 152.935063 37.1 seconds
154Er 153.932783 3.73 minutes
155Er 154.933209 5.3 minutes
156Er 155.931065 19.5 minutes
157Er 156.93192 18.65 minutes
158Er 157.929893 2.29 hours
159Er 158.930684 36 minutes
160Er 159.929083 28.58 hours
161Er 160.929995 3.21 hours
162Er 161.928778 Stable
163Er 162.930033 75.0 minutes
164Er 163.929200 Stable
165Er 164.930726 10.36 hours
166Er 165.9302931 Stable
167Er 166.9320482 Stable
167mEr   2.269 seconds
168Er 167.9323702 Stable
169Er 168.9345904 9.392 days
170Er 169.9354643 Stable
171Er 170.9380298 7.516 hours
172Er 171.939356 49.3 hours
173Er 172.94240 1.434 minutes
174Er 173.94423 3.2 minutes
175Er 174.94777 1.2 minutes
176Er 175.95008 ~20 seconds
177Er 176.95405 ~3 seconds

Precautions

As with the other lanthanides, erbium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail. Metallic erbium in dust form presents a fire and explosion hazard.

atom.gif (700 bytes)

Erbium Data

 

Atomic Structure

Atomic Radius (): 2.45
Atomic Volume cm3/mol : 18.4cm3/mol
Covalent Radius: 1.57
Crystal Structure: Hexagonal
Ionic Radius: 0.881

Chemical Properties

Electrochemical Equivalents: 2.0802g/amp-hr
Electron Work Function: unknown
Electronegativity: 1.24 (Pauling); 1.14 (Allrod Rochow)
Heat of Fusion: 19.9kJ/mol
First Ionization Potential: 6.101
Second Ionization Potential: 11.929
Third Ionization Potential: 22.739
Valence Electron Potential (-eV) : 49 -eV
Ionization Energy (eV): 6.108 eV

Physical Properties

Atomic Mass Average: 167.26
Boiling Point: 3136K, 2863C, 5185F
Melting Point: 1795K, 1522C, 2772F
Heat of Vaporization: 261 kJ/mol
Coefficient of Lineal Thermal Expansion/K-1: 9.2E-6
Electrical Conductivity: 0.0117 106/cm
Thermal Conductivity: 0.143 W/cmK
Density: 9.07 g/cm3 @ 300K
Enthalpy of Atomization: 314 kJ/mole @ 25C
Enthalpy of Fusion: 17.2 kJ/mole
Enthalpy of Vaporization: 261 kJ/mole
Molar Volume: 18.45 cm3/mole
Specific Heat: 0.17 J/gK
Vapor Pressure: unknown
Estimated Crustal Abundance: 3.5 milligrams per kilogram
Estimated Oceanic Abundance: 8.710-7 milligrams per liter