|Name, Symbol, Number||yttrium, Y, 39|
|Chemical series||transition metals|
|Group, Period, Block||3, 5, d|
|Atomic mass||88.90585(2) g/mol|
|Electron configuration||[Kr] 4d1 5s2|
|Electrons per shell||2, 8, 18, 9, 2|
|Density (near r.t.)||4.472 g/cm³|
|Liquid density at m.p.||4.24 g/cm³|
|Melting point||1799 K
(1526 °C, 2779 °F)
|Boiling point||3609 K
(3336 °C, 6037 °F)
|Heat of fusion||11.42 kJ/mol|
|Heat of vaporization||365 kJ/mol|
|Heat capacity||(25 °C) 26.53 J/(mol·K)|
(weakly basic oxide)
|Electronegativity||1.22 (Pauling scale)|
|1st: 600 kJ/mol|
|2nd: 1180 kJ/mol|
|3rd: 1980 kJ/mol|
|Atomic radius||180 pm|
|Atomic radius (calc.)||212 pm|
|Covalent radius||162 pm|
|Magnetic ordering||no data|
|Electrical resistivity||(r.t.) (α, poly) 596 nΩ·m|
|Thermal conductivity||(300 K) 17.2 W/(m·K)|
|Thermal expansion||(r.t.) (α, poly)
|Speed of sound (thin rod)||(20 °C) 3300 m/s|
|Speed of sound (thin rod)||(r.t.) 63.5 m/s|
|Shear modulus||25.6 GPa|
|Bulk modulus||41.2 GPa|
|Brinell hardness||589 MPa|
|CAS registry number||7440-65-5|
Yttrium (chemical symbol Y, atomic number 39) is a lustrous, silvery metal that is found in most rare-earth minerals. It is relatively stable in air, but its finely divided form is highly unstable in air. It was the "secret" element used in the production of the first high-temperature superconductor (yttrium barium copper oxide, or YBCO). Two of its compounds are used to make red-color phosphors for the picture tubes of color television sets, and others are used to produce infrared lasers.
Yttrium iron garnet is an effective microwave filter, and yttrium aluminum garnet is used as a gemstone. Yttrium is also used as a catalyst for certain reactions and in gas mantles for propane lanterns.
Yttrium occurs in nature in almost all rare-earth minerals and uranium ores, but never as a free element. It is commercially recovered from monazite sand (3 percent content) and bastnäsite (0.2 percent content). Interestingly, lunar rock samples retrieved by Apollo space missions were found to have a relatively high content of yttrium.
This element is difficult to separate from other rare-earth elements. It is commercially produced by reducing yttrium fluoride with calcium metal, but it can also be produced by other processes. When extracted, it appears as a dark gray powder.
Yttrium was discovered by Finnish chemist, physicist, and mineralogist Johan Gadolin in 1794. He isolated an impure form of its oxide, yttria (Y2O3), from one of the many unusual minerals found in a quarry near Ytterby, a small Swedish village near Vaxholm. Yttrium and yttria were named after this village. In addition, the elements erbium, terbium, and ytterbium were named after the same village.
In 1828, Friedrich Wöhler isolated yttrium by reducing anhydrous yttrium chloride (YCl3) with potassium. In 1843, the Swedish chemist Carl Mosander was able to show that yttria could be divided into the oxides (or earths) of three different elements. "Yttria" was the name used for the chemically most basic oxide, and the others were named erbia and terbia.
Yttrium is at the start of the series of transition metals in period 5 of the periodic table and is located between strontium and zirconium. In addition, it lies in group 3 (former group 3B), between scandium and lanthanum.
This rare earth metal is relatively stable in air and chemically resembles the lanthanides. Shavings or turnings of the metal can ignite in air at temperatures exceeding 400 °C. When yttrium is finely divided, it is very unstable in air. The metal has a low neutron cross-section for nuclear capture. The common oxidation state of yttrium is +3.
Natural yttrium is composed of only one isotope, Y-89, which is stable. In addition, many radioactive isotopes have been characterized. The radioactive isotope with the longest half-life is Y-88 (half-life of 106.65 days), followed by Y-91 (half-life of 58.51 days). Nearly all the other isotopes (except Y-87 and Y-90) have half-lives of less than a day. Y-90 exists in equilibrium with its parent isotope strontium-90, which is a product of nuclear explosions.
Yttrium has been studied for possible use as a nodulizer in the production of nodular cast iron, which has increased ductility. Potentially, yttrium can be used in ceramic and glass formulas, since yttrium oxide has a high melting point and imparts shock resistance and low thermal expansion characteristics to glass.
Compounds that contain this element are rarely encountered by most people and their toxicity is unclear. This element is not normally found in human tissue and plays no known biological role.
All links retrieved July 28, 2013.
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