 | |
| Names | |
|---|---|
| IUPAC name Yttrium(III) oxide. | |
| Other names Yttria, diyttrium trioxide, yttrium sesquioxide | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.013.849 |
| EC Number |
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| RTECS number |
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| UNII | |
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| Properties | |
| Y2O3 | |
| Molar mass | 225.81 g/mol |
| Appearance | White solid. |
| Density | 5.010 g/cm3, solid |
| Melting point | 2,425 °C (4,397 °F; 2,698 K) |
| Boiling point | 4,300 °C (7,770 °F; 4,570 K) |
| insoluble | |
| +44.4·10−6 cm3/mol[1] | |
| Structure | |
| Cubic (bixbyite),cI80[2] | |
| Ia3 (No. 206) | |
| Octahedral | |
| Thermochemistry | |
Std molar entropy(S⦵298) | 99.08 J/mol·K[3] |
Std enthalpy of formation(ΔfH⦵298) | −1905.310 kJ/mol[3] |
Gibbs free energy(ΔfG⦵) | −1816.609 kJ/mol[3] |
| Hazards | |
| Lethal dose or concentration (LD, LC): | |
LDLo (lowest published) | >10,000 mg/kg (rat, oral) >6000 mg/kg (mouse, oral)[4] |
| Related compounds | |
Otheranions | Yttrium(III) sulfide |
Othercations | Scandium(III) oxide, Lutetium(III) oxide |
Related compounds | Yttrium barium copper oxide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Yttrium oxide, also known asyttria, isY2O3. It is an air-stable, white solidsubstance.
Thethermal conductivity of yttrium oxide is 27 W/(m·K).[5]
Yttrium oxide is widely used to makeEu:YVO4 and Eu:Y2O3phosphors that give the red color in color TV picture tubes.
Y2O3 is a prospectivesolid-state laser material. In particular, lasers withytterbium asdopant allow the efficient operation both incontinuous operation[6] and in pulsed regimes.[7] At high concentration of excitations (of order of 1%) and poor cooling, the quenching of emission at laser frequency and avalanche broadband emission takes place.[8] (Yttria-based lasers are not to be confused with YAG lasers usingyttrium aluminium garnet, a widely used crystal host for rare earth laser dopants).
The original use of the mineral yttria and the purpose of its extraction from mineral sources was as part of the process of making gas mantles and other products for turning the flames of artificially-produced gases (initially hydrogen, later coal gas, paraffin, or other products) into human-visible light. This use is almost obsolete - thorium and cerium oxides are larger components of such products these days.
Yttrium oxide is used to stabilize theZirconia in late-generation porcelain-free metal-free dental ceramics. This is a very hard ceramic used as a strong base material in some full ceramic restorations.[9] The zirconia used in dentistry iszirconium oxide which has been stabilized with the addition ofyttrium oxide. The full name of zirconia used in dentistry is "yttria-stabilized zirconia" or YSZ.
Yttrium oxide is also used to makeyttrium iron garnets, which are very effectivemicrowave filters.[10]
Y2O3 is used to make thehigh temperature superconductor YBa2Cu3O7, known as "1-2-3" to indicate the ratio of the metal constituents:
This synthesis is typically conducted at 800 °C.
Yttrium oxide is an important starting point for inorganic compounds. For organometallic chemistry it is converted toYCl3 in a reaction with concentratedhydrochloric acid andammonium chloride.
Y2O3 is used in specialty coatings and pastes that can withstand high temperatures and act as a barrier for reactive metals such as uranium.[11]
NASA developed a material it dubbed Solar White that it is exploring for use as a radiator in deep space, where it is expected to reflect more than 99.9% of the sun’s energy (low solar radiation absorption and high infrared emittance).[12] A sphere covered with a 10 mm coating sited far from the Earth and 1astronomical unit from the sun could keep temperatures below 50 K. One use is long-term cryogenic storage.[13]
It's also used to create redphosphors for LED screens and TV tubes, as well as in anti-reflective coatings to enhance light transmission.[14]
Yttriaite-(Y), approved as a new mineral species in 2010, is the natural form of yttria. It is exceedingly rare, occurring as inclusions in nativetungsten particles in aplacer deposit of the Bol’shaja Pol’ja (Russian:Большая Полья) river, PrepolarUral,Siberia. As a chemical component of other minerals, the oxide yttria was first isolated in 1789 byJohan Gadolin, from rare-earth minerals in a mine at the Swedish town ofYtterby, nearStockholm.[15]
