Atomic number:65

Group numbers:3

Period:6

Electronic configuration:[Xe] 4f⁹ 6s²

Formal oxidation number:+3

Electronegativities:-

Atomic radius / pm:176.3

Relative atomic mass:158.92535 ± 0.00002

 

Terbium was discovered by Carl Gustaf Mosander (SE) in 1843. Named after Ytterby, a village in Sweden. It is a soft, ductile, silvery-grey, rare earth metal that oxidizes slowly in air and reacts with cold water. Terbium is found with other rare earths in monazite sand. Other sources are xenotime and euxenite, both of which are oxide mixtures that can contain up to 1% terbium. It is used in modest amounts in special lasers and solid-state devices.

Density / g dm^-3:8229 (293 K)

Molar volume / cm³mol^-1:19.31 (293 K)

Electrical resistivity / μΩcm:116 (20 °C)

Thermal conductivity / W m^-1K^-1:11.1

Melting point / °C:1356

Boiling point / °C:3230

Heat of fusion / kJ mol^-1:16.3

Heat of vaporization / kJ mol^-1:391

Heat of atomization / kJ mol^-1:390.62

1st ionization energy / kJ mol^-1:565.77

2nd ionization energy / kJ mol^-1:1111.52

3rd ionization energy / kJ mol^-1:2114.01

in the atmosphere / ppm:-

in the Earth's crust / ppm:0.6

in the oceans / ppm:0.0000014