Classé par:
Explorer
Name: erbium
Symbol: Er
Atomic number: 68
Atomic weight: 167.26 (3) g
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7440-52-0
Pure erbium metal is soft and malleable and has a bright, silvery, metallic lustre. As with other rare-earth metals, its properties depend to a certain extent on impurities present. The metal is fairly stable in air and does not oxidise as rapidly as some of the other rare-earth metals.
Name: hafnium
Symbol: Hf
Atomic number: 72
Atomic weight: 178.49 (2)
Group in periodic table: 4
Group name:
Period in periodic table: 6
Block in periodic table: d-block
CAS registry ID: 7440-58-6
Most zirconium minerals contain 1 to 3% hafnium. Hafnium is a ductile metal with a brilliant silver lustre. Its properties are influenced considerably by the impurities of zirconium present. Of all the elements, zirconium and hafnium are two of the most difficult to separate. Hafnium is a Group 4 transition element.
Because hafnium has a good absorption cross section for thermal neutrons (almost 600 times that of zirconium), has excellent mechanical properties, and is extremely corrosion resistant, it is used for nuclear reactor control rods.
Hafnium carbide is the most refractory binary composition known, and the nitride is the most refractory metal nitride (m.p. 3310°C).
Name: tantalum
Symbol: Ta
Atomic number: 73
Atomic weight: 180.9479 (1)
Group in periodic table: 5
Group name:
Period in periodic table: 6
Block in periodic table: d-block
CAS registry ID: 7440-25-7
Tantalum is a greyish silver, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which can be used as a filament for evaporating metals such as aluminium. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulphur trioxide. The element has a melting point exceeded only by tungsten and rhenium.
123456
Name: thulium
Symbol: Tm
Atomic number: 69
Atomic weight: 168.93421 (2)
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7440-30-4
Thulium is the least abundant of the earth elements, and is about as rare as silver, gold, or cadmium.
The pure metal has a bright, silvery lustre. It is reasonably stable in air, but the metal must be protected from moisture. The element is silvery-grey, soft, malleable, and ductile, and can be cut with a knife. It is a rare earth metal found in minerals such as monazite.
Name: lutetium
Symbol: Lu
Atomic number: 71
Atomic weight: 174.967 (1) g
Group in periodic table: 3
Group name: Lanthanoid
Period in periodic table: 6
Block in periodic table: d-block
CAS registry ID: 7439-94-3
Pure metal lutetium has been isolated only in recent years and is one of the more difficult to prepare. It can be prepared by the reduction of anhydrous LuCl3 or LuF3 by an alkali or alkaline earth metal.
The metal is silvery white and relatively stable in air. It is a rare earth metal and perhaps the most expensive of all rare elements. It is found in small amounts with all rare earth metals, and is very difficult to separate from other rare elements.
Name: dysprosium
Symbol: Dy
Atomic number: 66
Atomic weight: 162.50 (3) g
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7429-91-6
The element has a metallic, bright silver lustre. It is relatively stable in air at room temperature, but dissolves readily, with the evolution of hydrogen, in mineral acids. The metal is soft enough to be cut with a knife and can be machined without sparking if overheating is avoided. It is a rare earth metal found in minerals such as xenotime, monazite and bastanite.
123456
Name: terbium
Symbol: Tb
Atomic number: 65
Atomic weight: 158.92534 (2)
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7440-27-9
Terbium is reasonably stable in air. It is a silvery-grey metal, and is malleable, ductile, and soft enough to be cut with a knife. It is a rare earth metal found in cerite, gadolinite and monazite. The element itself was isolated only recently.
Name: samarium
Symbol: Sm
Atomic number: 62
Atomic weight: 150.36 (3) g
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7440-19-9
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 bastanite and is used in electronics industries.
Name: europium
Symbol: Eu
Atomic number: 63
Atomic weight: 151.964 (1) g
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7440-53-1
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: gadolinium
Symbol: Gd
Atomic number: 64
Atomic weight: 157.25 (3) g
Group in periodic table:
Group name: Lanthanoid
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7440-54-2
Gadolinium is silvery white, has a metallic lustre, and is is malleable and ductile. 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.