Thulium

Lanthanide · atomic number 69

69168.934222TmThuliumSolidLanthanide

Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.

Properties of Thulium

Element category	Lanthanide
Atomic number	69
Atomic mass	168.934222 u
Phase at STP	Solid
Group	3
Period	6
Block	f
Electron configuration	[Xe] 4f13 6s2
Electrons per shell	2, 8, 18, 31, 8, 2
Electronegativity (Pauling)	1.25
Melting point	1818 K (1545 °C)
Boiling point	2223 K (1950 °C)
Density	9.32 g/cm3
Discovered by	Per Teodor Cleve

← Erbium · Periodic table · Ytterbium → Yb

About the lanthanide group

The rare-earth “inner transition” metals that give strong permanent magnets, screen phosphors and catalyst polish.

Data: Periodic-Table-JSON (CC BY-SA 3.0) · stored statically on our server. https://en.wikipedia.org/wiki/Thulium

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