View source for Thallium(I) oxide

{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 447133761
| Name = Thallium(I) oxide
| ImageFile = Tl2Ostructure.jpg 
| ImageFile2 = Tl2Ostructure2.jpg 
| ImageName = 
| OtherNames = Thallous oxide
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 1314-12-1
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = LHV2O5DWPQ
| InChI =1/O.2Tl/q-2;2*+1
| EINECS = 215-220-4
| PubChem = 16684203
| SMILES = O([Tl])[Tl]
  }}
|Section2={{Chembox Properties
| Formula = Tl<sub>2</sub>O
| MolarMass = 424.77 g/mol
| Appearance = black [[orthorhombic]] crystals <br> [[hygroscopic]]
| Density = 10.45 g/cm<sup>3</sup>
| Solubility = soluble (reacts)
| SolubleOther = soluble in [[ethanol|alcohol]] and [[acid]]
| MeltingPtC = 596
| BoilingPtC = 1080
| BoilingPt_notes = (decomposes)
  }}
|Section3={{Chembox Structure
| CrystalStruct = [[Rhombohedral lattice system|Rhombohedral]], [[Pearson symbol|hR18]]<ref name=ZaaC>{{cite journal| journal = Zeitschrift für anorganische und allgemeine Chemie| year = 1971 | volume = 381 |page = 266| title = Zur Darstellung und Kristallstruktur von Tl<sub>2</sub>O| author = Sabrowsky H.|doi = 10.1002/zaac.19713810305| issue = 3}}</ref> 
| SpaceGroup = R-3m, No. 166
}}
|Section7={{Chembox Hazards
| ExternalSDS = 
| HPhrases = 
| PPhrases = 
| GHS_ref  = 
| NFPA-H = 
| NFPA-F = 
| NFPA-R = 
| NFPA-S = 
  }}
|Section8={{Chembox Related
| OtherCations = [[Thallium(III) oxide]]
  }}
}}

'''Thallium(I) oxide''' is the [[inorganic compound]] of [[thallium]] and [[oxygen]] with the formula Tl<sub>2</sub>O in which thallium is in its +1 [[oxidation state]]. It is black and produces a [[base (chemistry)|basic]] yellow solution of [[thallium(I) hydroxide]] (TlOH) when dissolved in water.  It is formed by heating solid TlOH or Tl<sub>2</sub>CO<sub>3</sub> in the absence of air.  Thallium oxide is used to make special high [[refractive index]] [[glass]].  Thallium oxide is a component of several [[High-temperature superconductivity|high temperature superconductor]]s. Thallium(I) oxide reacts with [[acid]]s to make thallium(I) salts.

Tl<sub>2</sub>O adopts the anti-[[cadmium iodide]] structure in the solid state.<ref name=ZaaC/>  In this way, the Tl(I) centers are pyramidal and the oxide centers are [[octahedral molecular geometry|octahedral]].

Thallium(I) oxide, like all thallium compounds, is highly toxic.

== Preparation ==
Thallium(I) oxide can be produced by decomposition of [[thallium(I) hydroxide]] at 100&nbsp;°C or by heating [[thallium(III) oxide]] in the absence of air to 700&nbsp;°C.<ref name="Simon Aldridge, Anthony J. Downs">{{cite book | last=Aldridge | first=S. | last2=Downs | first2=A. J. | title=The group 13 metals aluminium, gallium, indium and thallium : chemical patterns and peculiarities | publisher=Wiley | publication-place=Chichester, West Sussex | date=2011 | isbn=978-0-470-97655-5 | oclc=716206078 |page=325}}</ref>
:<math>\mathrm{2 \ TlOH \longrightarrow Tl_2 O + H_2 O}</math>
:<math>\mathrm{Tl_2O_3 \longrightarrow Tl_2 O + O_2}</math>

==References==
{{reflist}}

==External links==
* [http://minerals.usgs.gov/minerals/pubs/commodity/thallium/840303.pdf U.S. Geological Survey – Thallium]
* [http://www.encyclopedia.com/doc/1E1-thallium.html Extract from The Columbia Encyclopedia]

{{Thallium compounds}}
{{Oxides}}

[[Category:Thallium(I) compounds]]
[[Category:Oxides]]


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