Elements
69

Tm

Thulium

Pronounced

THOO-li-em

Thulium (Tm) is a silvery coloured metal that has the atomic number 69 in the periodic table. It is a Lanthanide metal. It has the symbol Tm.

The Swedish scientist Per Teodor Cleve discovered two new materials when he was working with the mineral Erbia. He discovered one green and one brown. The green ore turned out to me the oxide of Thulium. It was purified by Charles James in New Hampshire in 1911. Thullium is not very abundant on earth and exists in minerals and ores in the earths crust. Thulium is used in lasers with Yttrium and also used as the radioactive isotope Tm 170 in nuclear reactors. It is a solid metal at room temperature with a melting point of 1545°c and a boiling point of 1950°c.

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FAQ's

What is the Melting Point for Thulium?

Thulium has a Melting Point of 1545°C, meaning at 1545°C it will turn to a liquid.

What is the Boiling Point for Thulium?

Thulium has a Boiling Point of 1950°C, meaning at 1950°C it will turn to a Gas.

What is the Electronegativity of Thulium?

Thulium's Electronegativty is 1.25. Electronegativity is a measure of how strongly atoms attract bonding electrons to themselves.

Discovered by

Per Theodor Cleve

Discovery date

1879

What is the Heat of Vaporization of Thulium?

Thulium has a Heat of Vaporization of 191 kJ/mol.

Uses

Radioactive thulium is used to power portable x-ray machines, eliminating the need for electrical equipment.

Sources

Found with other rare earths in the minerals gadolinite, euxenite, xenotime, and monazite. Monazite is often 50% rare earth by weight and 0.007% thulium.

69
Protons
69
Electrons
100
Neutrons

Tm

Element Symbol
Tm
Atomic Weight
168.934
Atomic Number
69
State
Solid
Melting Point
Unknown
1545
°C
Boiling Point
1950
Unknown
°C
Heat of Vaporization
191
Unknown
kJ/mol
Crystal Structure
Hexagonal
Thermoconductivity
0.168
Unknown
W/cmK
Shells
2,8,18,31,8,2
Group
Lanthanide
Period
6
Block
F Block
Orbitals
[Xe] 4f13 6s2
Coefficient of Thermal Expansion
12 10^-6 K^-1
Covalent Radius
1.56 Å
Density at 293K
9.33 g/cm³
Electrical Conductivity
0.0150 10^6/cm ohm
First Ionization Potential
6.1843 V
Second Ionization Potential
12.054 V
Third Ionization Potential
26.367 V
Ionic Radius
1.09 (+3) Å
Oxydation States
(3),2
Lattice Parameter
3.5346 Å
Lattice Parameter 2
--
Lattice Parameter 3
5.0513 Å
Orbital configuration
2,8,18,31,8,2

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Explore Other Lanthanides

The lanthanide series contains 15 metallic elements from number 57 (lanthanum) to 71 (lutetium). They are located in group 3 and in the f-block of period six in the periodic table.
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Erbium

68
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Ytterbium

70