Erbium

Erbium, ₆₈Er
Erbium
Pronunciation	/ˈɜːrbiəm/ ⓘ (UR-bee-əm)
Appearance	silvery white
Standard atomic weight Ar°(Er)
	167.259±0.003; 167.26±0.01 (abridged);
Erbium in the periodic table
	holmium ← erbium → thulium
Atomic number (Z)	68
Group	f-block groups (no number)
Period	period 6
Block	f-block
Electron configuration	[Xe] 4f12 6s2
Electrons per shell	2, 8, 18, 30, 8, 2
Physical properties
Phase at STP	solid
Melting point	1802 K (1529 °C, 2784 °F)
Boiling point	3141 K (2868 °C, 5194 °F)
Density (at 20° C)	9.065 g/cm3
when liquid (at m.p.)	8.86 g/cm3
Heat of fusion	19.90 kJ/mol
Heat of vaporization	280 kJ/mol
Molar heat capacity	28.12 J/(mol·K)
Atomic properties
Oxidation states	common: +3; 0, +2
Electronegativity	Pauling scale: 1.24
Ionization energies	1st: 589.3 kJ/mol ; 2nd: 1150 kJ/mol ; 3rd: 2194 kJ/mol ; ;
Atomic radius	empirical: 176 pm
Covalent radius	189±6 pm
	Spectral lines of erbium
Other properties
Natural occurrence	primordial
Crystal structure	hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 355.93 pm; c = 558.49 pm (at 20 °C)
Thermal expansion	poly: 12.2 µm/(m⋅K) (r.t.)
Thermal conductivity	14.5 W/(m⋅K)
Electrical resistivity	poly: 0.860 µΩ⋅m (r.t.)
Magnetic ordering	paramagnetic at 300 K
Molar magnetic susceptibility	+44300.00×10−6 cm3/mol
Young's modulus	69.9 GPa
Shear modulus	28.3 GPa
Bulk modulus	44.4 GPa
Speed of sound thin rod	2830 m/s (at 20 °C)
Poisson ratio	0.237
Vickers hardness	430–700 MPa
Brinell hardness	600–1070 MPa
CAS Number	7440-52-0
History
Naming	after Ytterby (Sweden), where it was mined
Discovery	Carl Gustaf Mosander (1843)
First isolation	Wilhelm Klemm and Heinrich Bommer (1934)
Isotopes of erbium

Erbium is a chemical element; it has symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, originally found in the gadolinite mine in Ytterby, Sweden, which is the source of the element's name.

Erbium's principal uses involve its pink-colored Er³⁺ ions, which have optical fluorescent properties particularly useful in certain laser applications. Erbium-doped glasses or crystals can be used as optical amplification media, where Er³⁺ ions are optically pumped at around 980 or 1480 nm and then radiate light at 1530 nm in stimulated emission. This process results in an unusually mechanically simple laser optical amplifier for signals transmitted by fiber optics. The 1550 nm wavelength is especially important for optical communications because standard single mode optical fibers have minimal loss at this particular wavelength.

In addition to optical fiber amplifier-lasers, a large variety of medical applications (e.g. dermatology, dentistry) rely on the erbium ion's 2940 nm emission (see Er:YAG laser) when lit at another wavelength, which is highly absorbed in water in tissues, making its effect very superficial. Such shallow tissue deposition of laser energy is helpful in laser surgery, and for the efficient production of steam which produces enamel ablation by common types of dental laser.

^ "Standard Atomic Weights: Erbium". CIAAW. 1999.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ ^a ^b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
^ Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
^ All the lanthanides, except Pm, in the +2 oxidation state have been observed in organometallic molecular complexes, see Lanthanides Topple Assumptions and Meyer, G. (2014). "All the Lanthanides Do It and Even Uranium Does Oxidation State +2". Angewandte Chemie International Edition. 53 (14): 3550–51. doi:10.1002/anie.201311325. PMID 24616202.. Additionally, all the lanthanides (La–Lu) form dihydrides (LnH₂), dicarbides (LnC₂), monosulfides (LnS), monoselenides (LnSe), and monotellurides (LnTe), but for most elements these compounds have Ln³⁺ ions with electrons delocalized into conduction bands, e. g. Ln³⁺(H⁻)₂(e⁻).
^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[CIAAWerbium-1] "Standard Atomic Weights: Erbium". CIAAW. 1999.

[CIAAW2021-2] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[Arblaster_2018-3] Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.

[Cloke1993-4] Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.

[Lanthanides-5] All the lanthanides, except Pm, in the +2 oxidation state have been observed in organometallic molecular complexes, see Lanthanides Topple Assumptions and Meyer, G. (2014). "All the Lanthanides Do It and Even Uranium Does Oxidation State +2". Angewandte Chemie International Edition. 53 (14): 3550–51. doi:10.1002/anie.201311325. PMID 24616202.. Additionally, all the lanthanides (La–Lu) form dihydrides (LnH₂), dicarbides (LnC₂), monosulfides (LnS), monoselenides (LnSe), and monotellurides (LnTe), but for most elements these compounds have Ln³⁺ ions with electrons delocalized into conduction bands, e. g. Ln³⁺(H⁻)₂(e⁻).

[6] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[NUBASE2020-7] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

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