Yttrium

itrio ytrio

Yttrium is never found in pure form in nature, but there are small traces of it in many minerals, such as xenotime (yttrium phosphate, YPO4) and monazite.

Rock samples brought back from the Moon by the astronauts contained higher levels of yttrium than rocks on Earth.

Yttrium was discovered in a compound in 1794 by the chemist Johan Gadolin, but was not isolated until 1828. Since then, other yttrium compounds have been found in vegetables, such as cabbage, and in seeds of woody plants. In LED lamps, yttrium converts blue light into other colors. Many lasers use an artificial mixture of yttrium and aluminum inside a silicon-rich crystal called "garnet". Powerful yttrium lasers are used to treat some skin infections, as well as by dentists during dental surgery. A radioactive form of this element has medical applications. Yttrium is added to the glass in camera lenses to make it stronger. Yttrium compounds are also used in superconductors.

Chemical properties

Yttrium has a density of 4.5 g/cm3. Yttrium metal, along with the rare earth elements with which it is found, is usually produced by electrolysis of the chloride salt, as shown in the following chemical reaction:

2YCl3(l) → 2Y(s) + 3Cl2(g)

However, all the elements found with yttrium are so similar that the yttrium metal formed by electrolysis tends not to be completely pure. The best method for separating yttrium ions from other ions is ion exchange, in which a solution containing a mixture of the various ions is passed through a resin. The ions travel at different speeds depending on the relative charges and sizes of the ions. This process is called elution.

Yttrium chemistry is dominated by the "+3" oxidation state. At high temperatures, yttrium metal oxidizes to Y2O3. Only yttrium nitrate, Y(NO3)3, is soluble in water. Other common yttrium compounds are Y(OH)3, Y2(CO3)3, Y2(C2O4)3, YF3 and YPO4. Yttrium hydroxide is yellow in color and is slightly soluble in water. The other compounds are white and insoluble in water.

Summary of properties (Y)

Atomic weight88.90584(1)
Discoverer (year)Gadolin, Johan (1794)
Natural formmetallic solid (hexagonal)
Electron configuration[Kr] 4d1 5s2
Melting point (ºC)1523
Boiling point (ºC)3337
Abundance in earth's crust (ppm)33
Isotope (abundance)89Y (100)
Density g/cm34.47
Van der Waals radius (pm)232
Covalent radius (pm)176
Electronegativity (Pauling)1.22
Vaporization enthalpy (kJ/mol)393.00
Enthalpy of fusion (kJ/mol)11.40
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.30
Thermal conductivity (W/cm·K) at 25ºC and 1 atm0.170
Oxidation state+3
Electron affinity (eV)0.31
1st Ionization potential (eV)6.2173

Back to the Periodic Table of the Elements.