Thallium(I) hydroxide

Thallium(I) hydroxide, also called thallous hydroxide, is a chemical compound with the chemical formula TlOH. It is a hydroxide of thallium, with thallium in oxidation state +1. It is a thallium(I) salt of water. It consists of thallium(I) cations Tl⁺ and hydroxide anions OH⁻.

Thallium(I) hydroxide^[1]

Names
IUPAC name thallium(I) hydroxide
Other names thallous hydroxide
Identifiers
CAS Number	12026-06-1 Y
3D model (JSmol)	Interactive image
ChemSpider	141413 Y
ECHA InfoCard	100.031.540
EC Number	234-708-8
PubChem CID	160963
UNII	847N2ZKW5S Y
CompTox Dashboard (EPA)	DTXSID10894114
InChI InChI=1S/H2O.Tl/h1H2;/q;+1/p-1 Y Key: QGYXCSSUHCHXHB-UHFFFAOYSA-M Y InChI=1/H2O.Tl/h1H2;/q;+1/p-1 Key: QGYXCSSUHCHXHB-REWHXWOFAR
SMILES [Tl+].[OH-]
Properties
Chemical formula	TlOH
Molar mass	221.39 g·mol−1
Appearance	yellow needles
Density	7.44 g/cm3
Melting point	decomposes at 139°C
Solubility in water	34.3 g/(100 g) at 18°C
Thermochemistry
Std molar entropy (S⦵298)	88.0 J/(mol·K)
Std enthalpy of formation (ΔfH⦵298)	−238.9 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Very toxic Corrosive Dangerous for the environment
GHS labelling:[2]
Pictograms
Signal word	Danger
Hazard statements	H300, H330, H373, H411
Precautionary statements	P260, P264, P270, P271, P273, P284, P301+P310, P304+P340, P310, P314, P320, P330, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	4 0 1 COR
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis

Thallium(I) hydroxide is obtained from the decomposition of thallium(I) ethoxide in water.^[3]

CH₃CH₂OTl + H₂O → TlOH + CH₃CH₂OH

This can also be done by direct reaction of thallium with ethanol and oxygen gas.

4 Tl + 2 CH₃CH₂OH + O₂ → 2 CH₃CH₂OTl + 2 TlOH

Another method is the reaction between thallium(I) sulfate and barium hydroxide.

Tl₂SO₄ + Ba(OH)₂ → 2 TlOH + BaSO₄

Properties

Thallium(I) hydroxide is a strong base; it dissociates to thallium(I) cations, Tl⁺, and hydroxide anions, OH⁻, except in strongly basic conditions. Tl⁺ cation resembles an alkali metal cation, such as Li⁺, Na⁺ or K⁺.