Record Information
Version1.0
Creation Date2014-08-29 04:48:24 UTC
Update Date2026-04-06 04:25:08 UTC
Accession NumberCHEM002935
Identification
Common NameThallium
ClassSmall Molecule
DescriptionThallium is a chemical element with symbol Tl and atomic number 81. This soft gray post-transition metal is not found free in nature. When isolated, it resembles tin, but discolors when exposed to air. Thallium tends to oxidize to the +3 and +1 oxidation states as ionic salts. The +3 state resembles that of the other elements in thallium's group (boron, aluminum, gallium, indium). However, the +1 state, which is far more prominent in thallium than the elements above it, recalls the chemistry of alkali metals, and thallium(I) ions are found geologically mostly in potassium-based ores, and (when ingested) are handled in many ways like potassium ions (K+) by ion pumps in living cells. Thallium and its compounds are extremely toxic, and should be handled with great care. There are numerous recorded cases of fatal thallium poisoning. Contact with skin is dangerous, and adequate ventilation should be provided when melting this metal.
Contaminant Sources
  • Clean Air Act Chemicals
  • FooDB Chemicals
  • HMDB Contaminants - Urine
  • HPV EPA Chemicals
  • T3DB toxins
  • Tobacco Smoke Compounds
Contaminant Type
  • Indicator and Reagent
  • Industrial/Workplace Toxin
  • Inorganic Compound
  • Metabolite
  • Pollutant
  • Synthetic Compound
Chemical Structure
Thumb
Synonyms
ValueSource
THALLIUM (I) ionChEBI
Thallium, ion (TL1+)ChEBI
TL(+)ChEBI
Chemical FormulaTl
Average Molecular Mass204.383 g/mol
Monoisotopic Mass204.974 g/mol
CAS Registry Number7440-28-0
IUPAC Nameλ¹-thallanylium
Traditional Nameλ¹-thallanylium
SMILES[Tl+]
InChI IdentifierInChI=1S/Tl/q+1
InChI KeyZLUSCZLCHQSJRU-UHFFFAOYSA-N
Chemical Taxonomy
Description belongs to the class of inorganic compounds known as homogeneous post-transition metal compounds. These are inorganic compounds containing only metal atoms,with the largest atom being a post-transition metal atom.
KingdomInorganic compounds
Super ClassHomogeneous metal compounds
ClassHomogeneous post-transition metal compounds
Sub ClassNot Available
Direct ParentHomogeneous post-transition metal compounds
Alternative ParentsNot Available
Substituents
  • Homogeneous post-transition metal
Molecular FrameworkNot Available
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Extracellular
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological RolesNot Available
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceSilvery white solid.
Experimental Properties
PropertyValue
Melting Point303.5°C
Boiling Point1473 °C
SolubilityThallium(I) compounds have a high aqueous solubility.
Predicted Properties
PropertyValueSource
logP0.03ChemAxon
pKa (Strongest Acidic)1.11ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count0ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area0 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity0 m³·mol⁻¹ChemAxon
Polarizability1.78 ųChemAxon
Number of Rings0ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleNoChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyView
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0a4i-0090000000-41642f7e7845fd421f8dSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0a4i-0090000000-41642f7e7845fd421f8dSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0a4i-0090000000-41642f7e7845fd421f8dSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0090000000-202c86bb468a449bcce9Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0a4i-0090000000-202c86bb468a449bcce9Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0a4i-0090000000-202c86bb468a449bcce9Spectrum
Toxicity Profile
Route of ExposureDermal; inhalation; ingestion
Mechanism of ToxicityThallium(I) compounds have a high aqueous solubility and are readily absorbed through the skin. Part of the reason for thallium's high toxicity is that, when present in aqueous solution as the univalent thallium(I) ion (Tl+), it exhibits some similarities with essential alkali metal cations, particularly potassium (due to similar atomic radii). It can thus enter the body via potassium uptake pathways. Other aspects of thallium's chemistry differ strongly from that of the alkali metals, such its high affinity for sulfur ligands. Thus this substitution disrupts many cellular processes (for instance, thallium may attack sulfur-containing proteins such as cysteine residues and ferredoxins). (Wikipedia) A 2013 study found evidence that the thallium(I)-induced liver toxicity is a result of the disruptive effect of this metal on the mitochondrial respiratory complexes (I, II, and IV), which are the obvious causes of metal-induced reactive oxygen species formation and ATP depletion. The latter two events, in turn, trigger cell death signaling via opening of mitochondrial permeability transition pore and cytochrome c expulsion. (1)
MetabolismThallium is rapidly distributed throughout all tissues of the body. Most thallium is excreted by the faecal route but up to 35% may be excreted by the kidneys. (2)
Toxicity ValuesNot Available
Lethal DoseThe lethal dose is around 15 to 20 mg per kg body weight but serious toxicity and even death can occur with rather less. (2)
Carcinogenicity (IARC Classification)No indication of carcinogenicity to humans (not listed by IARC).
Uses/SourcesThallium(I) ions are found geologically mostly in potassium-based ores. Commercially, however, thallium is produced not from potassium ores, but as a byproduct from refining of heavy metal sulfide ores. Approximately 60–70% of thallium production is used in the electronics industry, and the remainder is used in the pharmaceutical industry and in glass manufacturing. It is also used in infrared detectors. The radioisotope thallium-201 (as the soluble chloride TlCl) is used in small, nontoxic amounts as an agent in a nuclear medicine scan, during one type of nuclear cardiac stress test. Soluble thallium salts were historically used in rat poisons and insecticides. Because of its historic popularity as a murder weapon, thallium has gained notoriety as "the poisoner's poison" and "inheritance powder" (alongside arsenic). (Wikipedia)
Minimum Risk LevelNot Available
Health EffectsAmong the distinctive effects of thallium poisoning are loss of hair (which led to its initial use as a depilatory before its toxicity was properly appreciated) and damage to peripheral nerves (victims may experience a sensation of walking on hot coals), although the loss of hair only generally occurs in low doses; in high doses the thallium kills before this can take effect. (Wikipedia) Thallium toxicity is complex and severe. It affects several systems in human body, including liver, gastrointestinal, cardiovascular, reproductive, renal, and nervous systems. Among them, liver is an important organ which possibly assists metabolic reduction of metals; hence, it could be a noticeable organ for thallium toxicity. This is confirmed by the other study on thallium-induced toxicity in experimental animals which reported highest accumulation in liver, kidney, and ileum. (1)
SymptomsNausea and vomiting; painful peripheral neuropathy; alopecia. (2)
TreatmentOne of the main methods of removing thallium (both radioactive and normal) from humans is to use Prussian blue, which is a material which absorbs thallium. Up to 20 g per day of Prussian blue is fed by mouth to the person, and it passes through their digestive system and comes out in the stool. Hemodialysis and hemoperfusion are also used to remove thallium from the blood serum. At later stage of the treatment additional potassium is used to mobilize thallium from the tissue.
Concentrations
Not Available
DrugBank IDNot Available
HMDB IDNot Available
FooDB IDNot Available
Phenol Explorer IDNot Available
KNApSAcK IDNot Available
BiGG IDNot Available
BioCyc IDNot Available
METLIN IDNot Available
PDB IDNot Available
Wikipedia LinkThallium
Chemspider IDNot Available
ChEBI ID49920
PubChem Compound ID105005
Kegg Compound IDNot Available
YMDB IDNot Available
ECMDB IDNot Available
References
Synthesis ReferenceNot Available
MSDSNot Available
General ReferencesNot Available