Gadolinium (64)

Gadolinium is silvery white, has a metallic luster, and is is malleable (capable of being extended or shaped by beating with a hammer or by the pressure of rollers) and ductile (capable of being drawn out into wire or threads). It is ferromagnetic (strongly attracted by a magnet).

The metal is relatively stable in dry air, but in moist air it tarnishes with the formation of a loosely adhering oxide film which "spalls" off and exposes more surface to oxidation. The metal reacts slowly with water and is soluble in dilute acid. Gadolinium has the highest thermal neutron capture cross-section of any known element. 

•Name: Gadolinium
•Symbol: Gd
•Atomic number: 64
•Atomic weight: 157.25 (3) [see note g]
•Standard state: solid at 298 K
•CAS Registry ID: 7440-54-2
•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
Gadolinium was discovered by Jean de Marignac at 1880 in Switzerland, and named for J. "Gadolin", a Finnish chemist and minerologist. Spectroscopic lines due to gadolinium were observed in samples of didymia and gadolinite. Gadolinia, the oxide of gadolinium, was separated by Paul-Emile Loq de Biosbaudran in 1886. The element was named for the mineral gadolinite from which this rare earth was originally obtained. The element itself was isolated only recently. 

Physical properties 
•Melting point: 1585 [or 1312 °C (2394 °F)] K
•Boiling point: 3523 [or 3250 °C (5882 °F)] K
•Density of solid: 7901 kg m-3

Orbital properties
•Ground state electron configuration: [Xe].4f7.5d1.6s2
•Shell structure: 2.8.18.25.9.2
•Term symbol: 9D2

Isolation
Gadolinium 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 gadolinium is available through the reduction of GdF3 with calcium metal.

2GdF3 + 3Ca → 2Gd + 3CaF2

This would work for the other calcium halides as well but the product CaF2 is easier to handle under the reaction conditions (heat to 50°C above the melting point of the element in an argon atmosphere). Excess calcium is removed from the reaction mixture under vacuum.

Europium (63)

Europium ignites in air at about 150 to 180°C. Europium is about as hard as lead and is quite ductile. It is the most reactive of the rare earth metals, quickly oxidising in air. It resembles calcium in its reaction with water. It is used in television screens to produce a red colour.

•Name: Europium
•Symbol: Eu
•Atomic number: 63
•Atomic weight: 151.964 (1) [see note g]
•Standard state: solid at 298 K
•CAS Registry ID: 7440-53-1
•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
Origin of name (betcha could've guessed this one!)- named after "Europe". The discovery of europium is generally credited to Eugene-Antole Demarcay, who separated the earth in reasonably pure form in 1901 from a material containing largely samarium. Pure europium metal was not isolated until much more recently. 

Physical properties 
•Melting point: 1099 [or 826 °C (1519 °F)] K
•Boiling point: 1800 [or 1527 °C (2781 °F)] K
•Density of solid: 5244 kg m-3

Orbital properties
•Ground state electron configuration: [Xe].4f7.6s2
•Shell structure: 2.8.18.25.8.2
•Term symbol: 8S7/2

Isolation
Europium 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 europium is available through the electrolysis of a mixture of molten EuCl3 and NaCl (or CaCl2) in a graphite cell which acts as cathode using graphite as anode. The other product is chlorine gas.

 

Samarium (62)

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.

 

Promethium (61)

PROMETHIUM [PRO-ME-THE-UM]
And no, it has nothing to do with that poor movie trying to be a prequel to ALIEN.

The essentials
Great care is required while handling promethium as a consequence of its radioactivity. Promethium salts luminesce in the dark with a pale blue or greenish glow, due to their high radioactivity. Ion-exchange methods led to the preparation of about 10 g of promethium from atomic reactor fuel processing wastes in early 1963.

Little is yet generally known about the properties of metallic promethium. More than 30 promethium compounds have been prepared. Promethium is a rare earth metal. It appears that there is no known Pm existing in the earth's crust.

•Name: Promethium
•Symbol: Pm
•Atomic number: 61
•Atomic weight: [ 145 ] 
•Standard state: solid at 298 K
•CAS Registry ID: 7440-12-2
•Group in periodic table: 
•Group name: Lanthanoid
•Period in periodic table: 6 (lanthanoid)
•Block in periodic table: f-block
•Colour: metallic
•Classification: Metallic

Historical information
Promethium was discovered by J. A. Marinsky, Lawrence Glendenin, Charles D. Coryell at 1945 in United States. Origin of name: named after "Prometheus" in Greek mythology, who stole fire from the gods. Early claims to the discovery of promethium date back to 1924 but these appear have been substantiated. A group at Ohio State University (USA) claimed element 61 in experiments involving its synthesis in a cyclotron, but again the evidence did not satisfy everyone. In 1947, Marinsky, Glendenin, and Coryell at Oak Ridge, Tennessee, USA, made the first chemical identification of promethium by use of ion-exchange chromatography on residues in a nuclear reactor.

Physical properties 
•Melting point: 1373 [or 1100 °C (2012 °F)] K
•Boiling point: 3273 [or 3000 °C (5432 °F)] K
•Density of solid: 7264 kg m-3

Orbital properties
•Ground state electron configuration: [Xe].4f5.6s2
•Shell structure: 2.8.18.23.8.2
•Term symbol: 6H5/2

Isolation
Promethium 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 promethium is available through the reduction of PmF3 with calcium metal.

2PmF3 + 3Ca → 2Pm + 3CaF2

This would work for the other calcium halides as well but the product CaF2 is easier to handle under the reaction conditions (heat to 50°C above the melting point of the element in an argon atmosphere). Excess calcium is removed from the reaction mixture under vacuum.

 

Neodymium (60)

Neodymium [KNEE-OH-DIM-EE-UM] is present in misch metal (an alloy of rare earth elements in various naturally occurring proportions) to the extent of about 18%. The metal has a bright silvery metallic lustre. Neodymium is one of the more reactive rare-earth metals and quickly tarnishes in air, forming an oxide that spalls off and exposes the metal to further oxidation. It is one of the rare earth metals.

•Name: Neodymium
•Symbol: Nd
•Atomic number: 60
•Atomic weight: 144.242 (3) [see note g]
•Standard state: solid at 298 K
•CAS Registry ID: 7440-00-8
•Group in periodic table: 
•Group name: Lanthanoid
•Period in periodic table: 6 (lanthanoid)
•Block in periodic table: f-block
•Color: silvery white, yellowish tinge
•Classification: Metallic

Historical information
Neodymium was discovered by Carl F. Auer von Welsbach at 1885 in Austria. Von Welsbach separated didymium, an extract of cerite, into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. Origin of name: from the Greek words "neos didymos" meaning "new twin". While the free metal is a component of misch metal, (a pyrophoric alloy for lighter flints), the element was not isolated in relatively pure form until 1925.

Physical properties 
•Melting point: 1297 [or 1024 °C (1875 °F)] K
•Boiling point: 3373 [or 3100 °C (5612 °F)] K
•Density of solid: 6800 kg m-3

Orbital properties
•Ground state electron configuration: [Xe].4f4.6s2
•Shell structure: 2.8.18.22.8.2
•Term symbol: 5I4

Isolation
Neodymium 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 neodymium is available through the reduction of NdF3 with calcium metal.

2NdF3 + 3Ca → 2Nd + 3CaF2

This would work for the other calcium halides as well but the product CaF2 is easier to handle under the reaction conditions (heat to 50°C above the melting point of the element in an argon atmosphere). Excess calcium is removed from the reaction mixture under vacuum.