Samarium has a bright silver lustre and is reasonably stable
in air. It ignites in air at 150°C. It is a rare earth metal. It is found with
other rare earth elements in minerals including monazite and bastnaesite and is
used in electronics industries.
•Name: Samarium
•Symbol: Sm
•Atomic number: 62
•Atomic weight: 150.36 (2) [see note g]
•Standard state: solid at 298 K
•CAS Registry ID: 7440-19-9
•Group in periodic table:
•Group name: Lanthanoid
•Period in periodic table: 6 (lanthanoid)
•Block in periodic table: f-block
•Color: silvery white
•Classification: Metallic
Historical information
Samarium was discovered by Paul Emile Lecoq de Boisbaudran at 1879 in France. The element was isolated in 1879 by Lecoq de Boisbaudran from the mineral samarskite, named in honour of a Russian mine official, Colonel Samarski, and which therefore gave samarium its name. Samarium was discovered spectroscopically by its sharp absorption lines in 1853 by Jean Charles Galissard de Marignac in an "earth" called didymia.
Physical properties
•Melting point: 1345 [or 1072 °C (1962 °F)] K
•Boiling point: 2076 [or 1803 °C (3277 °F)] K
•Density of solid: 7353 kg m-3
Oorbital properties
•Ground state electron configuration: [Xe].4f6.6s2
•Shell structure: 2.8.18.24.8.2
•Term symbol: 7F0
Isolation
Samarium metal is available commercially so it is not normally necessary to make it in the laboratory, which is just as well as it is difficult to isolate as the pure metal. This is largely because of the way it is found in nature. The lanthanoids are found in nature in a number of minerals. The most important are xenotime, monazite, and bastnaesite. The first two are orthophosphate minerals LnPO4 (Ln deonotes a mixture of all the lanthanoids except promethium which is vanishingly rare) and the third is a fluoride carbonate LnCO3F. Lanthanoids with even atomic numbers are more common. The most comon lanthanoids in these minerals are, in order, cerium, lanthanum, neodymium, and praseodymium. Monazite also contains thorium and ytrrium which makes handling difficult since thorium and its decomposition products are radioactive.
For many purposes it is not particularly necessary to separate the metals, but if separation into individual metals is required, the process is complex. Initially, the metals are extracted as salts from the ores by extraction with sulphuric acid (H2SO4), hydrochloric acid (HCl), and sodium hydroxide (NaOH). Modern purification techniques for these lanthanoid salt mixtures are ingenious and involve selective complexation techniques, solvent extractions, and ion exchange chromatography.
Pure samarium is available through the electrolysis of a mixture of molten SmCl3 and NaCl (or CaCl2) in a graphite cell which acts as cathode using graphite as anode. The other product is chlorine gas.
•Name: Samarium
•Symbol: Sm
•Atomic number: 62
•Atomic weight: 150.36 (2) [see note g]
•Standard state: solid at 298 K
•CAS Registry ID: 7440-19-9
•Group in periodic table:
•Group name: Lanthanoid
•Period in periodic table: 6 (lanthanoid)
•Block in periodic table: f-block
•Color: silvery white
•Classification: Metallic
Historical information
Samarium was discovered by Paul Emile Lecoq de Boisbaudran at 1879 in France. The element was isolated in 1879 by Lecoq de Boisbaudran from the mineral samarskite, named in honour of a Russian mine official, Colonel Samarski, and which therefore gave samarium its name. Samarium was discovered spectroscopically by its sharp absorption lines in 1853 by Jean Charles Galissard de Marignac in an "earth" called didymia.
Physical properties
•Melting point: 1345 [or 1072 °C (1962 °F)] K
•Boiling point: 2076 [or 1803 °C (3277 °F)] K
•Density of solid: 7353 kg m-3
Oorbital properties
•Ground state electron configuration: [Xe].4f6.6s2
•Shell structure: 2.8.18.24.8.2
•Term symbol: 7F0
Isolation
Samarium metal is available commercially so it is not normally necessary to make it in the laboratory, which is just as well as it is difficult to isolate as the pure metal. This is largely because of the way it is found in nature. The lanthanoids are found in nature in a number of minerals. The most important are xenotime, monazite, and bastnaesite. The first two are orthophosphate minerals LnPO4 (Ln deonotes a mixture of all the lanthanoids except promethium which is vanishingly rare) and the third is a fluoride carbonate LnCO3F. Lanthanoids with even atomic numbers are more common. The most comon lanthanoids in these minerals are, in order, cerium, lanthanum, neodymium, and praseodymium. Monazite also contains thorium and ytrrium which makes handling difficult since thorium and its decomposition products are radioactive.
For many purposes it is not particularly necessary to separate the metals, but if separation into individual metals is required, the process is complex. Initially, the metals are extracted as salts from the ores by extraction with sulphuric acid (H2SO4), hydrochloric acid (HCl), and sodium hydroxide (NaOH). Modern purification techniques for these lanthanoid salt mixtures are ingenious and involve selective complexation techniques, solvent extractions, and ion exchange chromatography.
Pure samarium is available through the electrolysis of a mixture of molten SmCl3 and NaCl (or CaCl2) in a graphite cell which acts as cathode using graphite as anode. The other product is chlorine gas.
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