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Samarium - Sm

Chemical properties of samarium - Health effects of samarium - Environmental effects of samarium

Atomic number


Atomic mass

150.35 g.mol -1

Electronegativity according to Pauling



6.9 g.cm-3 at 20°C

Melting point

1072 °C

Boiling point

1790 °C

Vanderwaals radius


Ionic radius




Electronic shell

[ Xe ] 4f6 6s2

Energy of first ionisation

542.3 kJ.mol -1

Energy of second ionisation

1066 kJ.mol -1

Standard potential

- 2.41 V

Discovered by

Paul Emile Lecoq de Boisbaudran in 1879

Samarium - Sm


Samarium is a silvery-white metal belonging to the lanthanide group of the periodic table. It is relatively stable at room temperature in dry air, but it ignites when heated above 150 C and forms an oxide coating in moist air. Like europium samarium has a relatively stable oxidation state (II).


Samarium is used as a catalyst in certain organic reactions: the samarium iodide (SmI2) is used by organic research chemists to make synthetic versions of natural products. The oxide, samaria, is used for making special infrared adsorbing glass and cores of carbon arc-lamp electrodes and as a catalyst for the dehydration and dehydrogenation of ethanol. Its compound with cobalt (SmCo5) is used in making a new permanent magnet material.

Samarium in the environment

Samarium is the fifth most abundant of the rare elements and is almost four times as common as tin. It is never found free in nature, but in contained in many minerals, including monazite, bastnasite and samarskite. Samarium containing ores are found in USA, China, Brazil, India, Australia and Sri Lanka. World production of samarium oxide is about 700 tonnes per year and world-wide reserves are estimated to be around 2 million tonnes.

Health effects of samarium

Samarium has no biological role, but it has been noted to stimulate metabolism. Soluble samarium salts are mildly toxic by ingestion and there are health hazards associated with these because exposure to samarium causes skin and eye irritation.

Effects of samarium on the environment

Samarium does not poses any threat to plants or animals.

Sources of periodic table.

Back to the periodic table of elements.

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