View source for Terbium(III) oxide

{{chembox
| Watchedfields  = changed
| verifiedrevid  = 451892662
| ImageFile      = Tl2O3structure.jpg
| ImageSize      = 
| IUPACName      = terbium(III) oxide
| OtherNames     = terbium trioxide, terbia, terbium sesquioxide
| Section1       = {{Chembox Identifiers
| Abbreviations = 
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12036-41-8
| EINECS = 234-849-5
| PubChem = 159410
| SMILES = [O-2].[O-2].[O-2].[Tb+3].[Tb+3] 
| InChI = 1/3O.2Tb/q3*-2;2*+3
| RTECS =
| MeSHName =
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI =
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = 
}}
| Section2       = {{Chembox Properties
| Tb=2 | O=3
| Formula = 
| MolarMass =
| Appearance = white crystals
| Density = 7.91 g/cm<sup>3</sup>
| MeltingPtC = 2410
| MeltingPt_notes =
| BoilingPt = 
| BoilingPt_notes = 
| Solubility = 
| SolubleOther = 
| MagSus = 0.07834 cm<sup>3</sup>/mol
| Solvent = 
| pKa = 
| pKb = 
}}
| Section3       = {{Chembox Structure
| CrystalStruct = [[Cubic crystal system|Cubic]], [[Pearson symbol|cI80]]
| SpaceGroup = Ia{{overline|3}}, No. 206<ref>{{cite journal| journal = J. Phys. F| year = 1973 | volume = 3| issue = 1 | pages = 1–5| title = The observation of face centred cubic Gd, Tb, Dy, Ho, Er and Tm in the form of thin films and their oxidation|doi=10.1088/0305-4608/3/1/009|author1=Curzon A.E. |author2=Chlebek H.G. | bibcode = 1973JPhF....3....1C }}</ref>
| LattConst_a = 1.057 nm
}}
| Section4       = {{Chembox Thermochemistry
| DeltaGf = −1776.553 kJ/mol <ref name=usgs>R. Robie, B. Hemingway, and J. Fisher, "Thermodynamic Properties of Minerals and Related Substances at 298.15K and 1bar Pressure and at Higher Temperatures," US Geol. Surv., vol. 1452, 1978.[https://pubs.usgs.gov/bul/1452/report.pdf]</ref>
| DeltaHc = 
| DeltaHf = −1865.23 kJ/mol <ref name=usgs />
| Entropy = 156.90 J/mol·K <ref name=usgs />
| HeatCapacity = 
  }}
| Section7       = {{Chembox Hazards
| MainHazards = 
| NFPA-H = 
| NFPA-F = 
| NFPA-R = 
| NFPA-S =
| GHSPictograms = {{GHS07}}{{GHS09}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|319|410}}
| PPhrases = {{P-phrases|264|273|280|305+351+338|337+313|391|501}}
| FlashPt = 
| AutoignitionPt = 
| ExploLimits = 
| PEL = }}
| Section8       = {{Chembox Related
| OtherAnions = [[Terbium(III) chloride]]
| OtherCations = [[Gadolinium(III) oxide]]<br>[[Dysprosium(III) oxide]]
  }}
}}

'''Terbium(III) oxide''', also known as '''terbium sesquioxide''', is a [[sesquioxide]] of the rare earth metal [[terbium]], having [[chemical formula]] {{chem|Tb|2|O|3}}. It is a p-type [[semiconductor]], which conducts protons, which is enhanced when doped with [[calcium]].<ref>{{cite journal|journal=Solid State Ionics|volume=176|issue=39&ndash;40|date=December 2005|pages=2957&ndash;2961|doi=10.1016/j.ssi.2005.09.030|publisher=Elsevier B.V.|title=Proton conductivity of Ca-doped {{chem|Tb|2|O|3}}|author1=Reidar Haugsrud |author2=Yngve Larring |author3=Truls Norby  |name-list-style=amp }}</ref> It may be prepared by the reduction of [[Terbium(III,IV) oxide|{{chem|Tb|4|O|7}}]] in [[hydrogen]] at 1300&nbsp;°C for 24 hours.<ref>{{cite journal|journal=Journal of Applied Crystallography|volume=4|issue=5|date=October 1971|pages=399&ndash;400|doi=10.1107/S0021889871007295|title=Crystal data on C-type terbium sesquioxide ({{chem|Tb|2|O|3}})|author=G. J. McCarthy}}</ref>

:{{chem2|Tb4O7 + H2 -> 2 Tb2O3 + H2O}}

It is a basic oxide and easily dissolved to dilute acids, and then almost colourless terbium salt is formed.
: Tb<sub>2</sub>O<sub>3</sub> + 6 H<sup>+</sup> → 2 Tb<sup>3+</sup> + 3 H<sub>2</sub>O

The crystal structure is [[cubic crystal system|cubic]] and the [[lattice constant]] is ''a'' = 1057 pm.<ref name="Baenzinger">N. C. Baenzinger, H. A. Eick, H. S. Schuldt, L. Eyring: ''Terbium Oxides. III. X-Ray Diffraction Studies of Several Stable Phases''. In: ''[[Journal of the American Chemical Society]]'', 1961, 83, 10, S. 2219-23.</ref>

==References==
{{reflist}}

{{Terbium compounds}}
{{Oxides}}

[[Category:Terbium compounds]]
[[Category:Sesquioxides]]
[[Category:Semiconductor materials]]


{{inorganic-compound-stub}}