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Pm
61
Sm
62
Eu
63
Np
93
Pu
94
Am
95

 

Periodic table

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Samarium

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Samarium

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Samarium

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Samarij

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Samario

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Samario

 

Sm
Sm
Samarium

PERIODIC TABLE OF THE ELEMENTS

SAMARIUM

TRANSITION ELEMENT:
LANTHANIDE

 

Atomic number:62

Group numbers:3

Period:6

Electronic configuration:[Xe] 4f6 6s2

Formal oxidation number:+2 +3

Electronegativities:1.17

Atomic radius / pm:180.4

Relative atomic mass:150.36 ± 0.02

 

Samarium was discovered by Paul-Émile Lecoq de Boisbaudran (FR) in 1879. Named after the mineral samarskite. It is a silvery rare earth metal that is stable in dry air but reacts with water. Oxide coating forms on surfaces exposed to moist air and the metal ignites and burns readily. Samarium is found with other rare earths in monazite sand. It is used in the electronics and ceramics industries. It is easily magnetized and very difficult to demagnetise. This suggests important future applications in solid-state and superconductor technologies.

PHYSICAL PROPERTIES

Density / g dm-3:7520 (293 K)

Molar volume / cm3mol-1:19.99 (293 K)

Electrical resistivity / μΩcm:88 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:13.3

Melting point / °C:1074

Boiling point / °C:1794

Heat of fusion / kJ mol-1:10.9

Heat of vaporization / kJ mol-1:164.8

Heat of atomization / kJ mol-1:206.1

IONIZATION ENERGIES

First ionization energy / kJ mol-1:544.53

Second ionization energy / kJ mol-1:1068.10

Third ionization energy / kJ mol-1:2257.77

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:3.5

in the oceans / ppm:0.0000002

CRYSTALLOGRAPHIC DATA

rhombohedral

Crystal structure:

rhombohedral

Unit-cell dimensions / pm:

a=899.6, α=23°13'

Space group:

R3m

ISOTOPES

IsotopeRelative atomic massMass percent (%)
144Sm143.911995(4)3.1(1)
147Sm146.914893(3)15.0(2)
148Sm147.914818(3)11.3(1)
149Sm148.917180(3)13.8(1)
150Sm149.917271(3)7.4(1)
152Sm151.919728(3)26.7(2)
154Sm153.922205(3)22.7(2)

REDUCTION POTENTIALS

Balanced half-reaction Eo / V

 

61 Promethium <=
62 Samarium
=> 63 Europium