Electronic data		Thermal data		Steric 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		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		Atomic radius: 2.51 Å Ionic radius: 1.18 Å () 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,+,	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,-	View
159Tb	100	159.925	3/2	--	stable	--
160Tb	0	160	3	72.3d	-	View
161Tb	0	161	3/2	6.91d	-	View
162Tb	0	162	1	7.6m	-	View

Legend

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.