Yttrium

General
Name, Symbol, Number	Yttrium, Y, 39
Chemical series	transition metals
Group, Period, Block	3 , 5 , d
Density, Hardness	4472 kg/m3, __
Appearance	Silvery white
Atomic Properties
Atomic weight	88.90585 amu
Atomic radius (calc.)	180 (212) pm
Covalent radius	162 pm
van der Waals radius	no data
Electron configuration	[Kr]4d15s2
e- 's per energy level	2, 8, 18, 9, 2
Oxidation states (Oxide)	3 (weak base)
Crystal structure	Hexagonal
Physical Properties
State of matter	Solid (__)
Melting point	1799 K (2779 °F)
Boiling point	3609 K (6037 °F)
Molar volume	19.88 ×10-3 m3/mol
Heat of vaporization	363 kJ/mol
Heat of fusion	11.4 kJ/mol
Vapor pressure	5.31 Pa at 1799 K
Velocity of sound	3300 m/s at 293.15 K
Miscellaneous
Electronegativity	1.22 (Pauling scale)
Specific heat capacity	300 J/(kg*K)
Electrical conductivity	1.66 106/m ohm
Thermal conductivity	17.2 W/(m*K)
1st ionization potential	1980 kJ/mol
2nd ionization potential	5847 kJ/mol
3rd ionization potential	7430 kJ/mol
4th ionization potential	5847 kJ/mol
5th ionization potential	7430 kJ/mol
6th ionization potential	8970 kJ/mol
7th ionization potential	11190 kJ/mol
8th ionization potential	12450 kJ/mol
9th ionization potential	14110 kJ/mol
10th ionization potential	18400 kJ/mol
Most Stable Isotopes
iso NA Longest t½ is 106.65 d (Y-88) 89Y 100% Y is stable with 50 neutrons
SI units & STP are used except where noted.

Yttrium is a chemical element in the periodic table that has the symbol Y and atomic number 39. A silvery metallic transition metal, yttrium is common in rare-earth minerals and two of its compounds are used to make the red color in color televisions.

Notable Characteristics

Yttrium is a silver-metallic, lustrous rare earth metal that is relatively stable in air and chemically resembles the lanthanides. Shavings ("turnings") of the metal can ignite in air when they exceed 400 °C. When yttrium is finely divided it is very unstable in air. The metal has a low cross section for nuclear capture. The common oxidation state of yttrium is +3.

Applications

Yttrium oxide is the most important yttrium compound and is widely used to make YVO₄ europium and Y₂O₃ europium phosphors that give the red color in color television picture tubes. Other uses;

• Yttrium oxide is also used to make yttrium-iron-garnets which are very effective microwave filters.
• Yttrium iron, aluminum, and gadolinium garnets (e.g. Y₃Fe₅O₁₂ and Y₃Al₅O₁₂) have interesting magnetic properties. Yttrium iron garnet is very efficient as an acoustic energy transmitter and transducer. Yttrium aluminum garnet has a hardness of 8.5 and is also used as a gemstone (simulated diamond).
• Small amounts of the element (0.1 to 0.2%) have been used to reduce grain size of chromium, molybdenum, titanium, and zirconium. It is also used to increase the strength of aluminum and magnesium alloys.
• Used as a catalyst for ethylene polymerization in laser systems.
• This metal can be used to deoxidize vanadium and other nonferrous metals.

Yttrium has been studied for possible use as a nodulizer in the making of nodular cast iron which has increased ductility (the graphite forms compact nodules instead of flakes to form nodular cast iron). Potentially, yttrium can be used in ceramic and glass formulas, since yttrium oxide has a high melting point and imparts shock resistance and low expansion characteristics to glass.

History

Yttrium (Ytterby, a Swedish village near Vauxholm) was discovered by Friedrich Wohler in 1928 as an impure extract of yttria through the reduction of yttrium anhydrous chloride (YCl₃) with potassium. Yttria (Y₂O₃) is the oxide of yttruim and was discovered by Johan Gadolin in 1794 in a gadolinite mineral from Ytterby.

In 1843 Carl Mosander was able to show that yttira could be divided into the oxides (or earths) of three different elements. "Yttria" was the name used for the most basic one and the others were named erbia and terbia.

A quarry is located near the village of Ytterby that yielded many unusual minerals that contained rare earths and other elements. The elements erbium, terbium, and ytterbium and yttrium have all been named after this same town.

Occurrence

This element is found in almost all rare earth minerals and in uranium ores but is never found in nature as a free element. Yttrium is commercially recovered from monazite sand (3% content, [(Ce, La, etc.)PO₄]) and from bastnasite (0.2% content, [(Ce, La, etc.)(CO₃)F]). It is commercially produced by reducing yttrium fluoride with calcium metal but it can also be produced using other techniques. It is difficult to separate from other rare earths and when extracted, is a dark gray powder.

Lunar rock samples from the Apollo program have a relatively high yttrium content.

Isotopes

Natural yttrium is composed of only one isotope (Y-89). The most stable radioisotopes are Y-88 which has a half life of 106.65 days and Y-91 with a half life of 58.51 days. All the other isotopes have half lifes of less than a day except Y-87 which has a half life of 79.8 hours. The dominant decay mode below the stable Y-89 is electron capture and the dominant mode after it is beta emission. Twenty six unstable isotopes have been characterized.

Y-90 exists in equilibrium with its parent isotope strontium-90, which is a product of nuclear explosions.

Precautions

Compounds that contain this element are rarely encountered by most people but should be considered to be highly toxic even though many compounds pose little risk. Yttrium salts may be cancerous. This element is not normally found in human tissue and plays no known biological role.

External Links

• WebElements.com - Yttrium
• EnvironmentalChemistry.com - Yttrium