Terbium

Terbium, ₆₅Tb

Terbium
Pronunciation	/ˈtɜːrbiəm/ ​(TUR-bee-əm)
Appearance	silvery white
Standard atomic weight Ar°(Tb)
	158.925354(8)
Terbium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ Tb ↓ Bk gadolinium ← terbium → dysprosium
Atomic number (Z)	65
Group	f-block groups (no number)
Period	period 6
Block	f-block
Electron configuration	[Xe] 4f9 6s2
Electrons per shell	2, 8, 18, 27, 8, 2
Physical properties
Phase at STP	solid
Melting point	1629 K ​(1356 °C, ​2473 °F)
Boiling point	3396 K ​(3123 °C, ​5653 °F)
Density (near r.t.)	8.23 g/cm3
when liquid (at m.p.)	7.65 g/cm3
Heat of fusion	10.15 kJ/mol
Heat of vaporization	391 kJ/mol
Molar heat capacity	28.91 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1789 1979 (2201) (2505) (2913) (3491)
Atomic properties
Oxidation states	0, +1, +2, +3, +4 (a weakly basic oxide)
Electronegativity	Pauling scale: 1.2 (?)
Ionization energies	1st: 565.8 kJ/mol 2nd: 1110 kJ/mol 3rd: 2114 kJ/mol
Atomic radius	empirical: 177 pm
Covalent radius	194±5 pm
Spectral lines of terbium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp)
Speed of sound thin rod	2620 m/s (at 20 °C)
Thermal expansion	at r.t. α, poly: 10.3 µm/(m⋅K)
Thermal conductivity	11.1 W/(m⋅K)
Electrical resistivity	α, poly: 1.150 µΩ⋅m (at r.t.)
Magnetic ordering	paramagnetic at 300 K
Molar magnetic susceptibility	+146000×10−6 cm3/mol (273 K)
Young's modulus	α form: 55.7 GPa
Shear modulus	α form: 22.1 GPa
Bulk modulus	α form: 38.7 GPa
Poisson ratio	α form: 0.261
Vickers hardness	450–865 MPa
Brinell hardness	675–1200 MPa
CAS Number	7440-27-9
History
Naming	after Ytterby (Sweden), where it was mined
Discovery and first isolation	Carl Gustaf Mosander (1843)
Isotopes of terbium v e
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 157Tb synth 71 y ε 157Gd 158Tb synth 180 y ε 158Gd β− 158Dy 159Tb 100% stable
Category: Terbium view talk edit | references

Terbium is a chemical element that has the symbol Tb on the periodic table. It has the atomic number 65 which means it has 65 protons in an atom. Its compounds fluoresce green in ultraviolet light. The metal can burned in air to form an oxide. It is a lanthanide and, along with yttrium, erbium, and ytterbium, is one of the four elements to be named after the town of Ytterby in Sweden, all of which are rare earth elements.

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1. ↑ "Standard Atomic Weights: Terbium". CIAAW. 2017.
2. ↑ 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.
3. ↑ La(I), Pr(I), Tb(I), Tm(I), and Yb(I) have been observed in MB₈⁻ clusters; see Li, Wan-Lu; Chen, Teng-Teng; Chen, Wei-Jia; Li, Jun; Wang, Lai-Sheng (2021). "Monovalent lanthanide(I) in borozene complexes". Nature Communications. 12 (1): 6467. doi:10.1038/s41467-021-26785-9. PMC 8578558. PMID 34753931.{{cite journal}}: CS1 maint: unflagged free DOI (link)
4. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
5. ↑ 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.