Terbium

Metal

Symbol: Tb
Atomic number: 65
Atomic mass: 158.92534
Group: Lanthanide
CAS-number: 7440-27-9

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Electronic data

Shells: 2, 8, 18, 27, 8, 2
Orbitals: [Xe] 4f⁹ 6s²
Electronegativity: --, 1.1
1. Ionization potential: 5.8639 eV
2. Ionization potential: 11.525 eV
3. Ionization potential: 21.91 eV
Oxidation states: 4, 3
Electrical conductivity: 0.00889 10^6

Thermal data

Melting point: 1356 °C
Boiling point: 3230 °C
Specific heat: 0.18 J/gK
Heat of fusion: 10.80 kJ/mol
Heat of vaporization: 330.90 kJ/mol
Thermal conductivity: 0.111 W/cmK

Steric data

Atomic radius: 2.51 Å
Ionic radius: 1.18 Å (+3)
Covalent radius: 1.59 Å
Atomic volume: 19.2 cm³/mol
Density (293 K): 8.27 g/cm³
Crystal structure: hexagonal

Nuclide	Abundance [%]	Mass	Spin	Halflife	Decay mode	Decay tree
¹⁵¹Tb	0	151	1/2	17.61h	EC, β+, α	View
¹⁵⁵Tb	0	155	3/2	5.3d	EC	View
¹⁵⁶Tb	0	156	3	5.3d	EC	View
¹⁵⁷Tb	0	157	3/2	1.1E02y	EC	View
¹⁵⁸Tb	0	158	3	1.8E02y	EC, β-	View
¹⁵⁹Tb	100	159.925	3/2	--	--
¹⁶⁰Tb	0	160	3	72.3d	β-	View
¹⁶¹Tb	0	161	3/2	6.91d	β-	View
¹⁶²Tb	0	162	1	7.6m	β-	View

Name origin:	Named after Ytterby, a village in Sweden.
Description:	Soft, ductile, silvery-gray, rare earth metal.
Discovered by:	Carl Mosander
Year:	1843
Place:	Sweden
Sources:	Found with other rare earths in monazite sand, which typically contain 0.03% terbium. Other sources are xenotime and euxenite, both of which are oxide mixtures that can contain up to 1% terbium.
Use(s):	It is used in modest amounts in special lasers and solid-state devices.

Terbium

Physical data

Electronic data

Thermal data

Steric data

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