Basic information
- CAS
7440-13-3- Standard SMILES
[Pa]- InChIKey
XLROVYAPLOFLNU-UHFFFAOYSA-N- Molecular formula
- Pa
- Average molar mass
- 231.0359 g/mol
- Monoisotopic mass
- 231.03588
Overview
Protactinium atom is an actinoid atom and a f-block element atom.
Names & identifiers
- Preferred name
- Protactinium
- IUPAC
- protactinium
- English name
- Protactinium
- Molecular formula
- Pa
- Molecular weight
- 231.03588
Names & synonyms
PROTACTINIUMprotoactinium7440-13-3brevium0S6855V29MDTXSID50225387RefChem:176641DTXCID50147878616-087-9Paprotactinium atomprotactinio
Show more names
91PaChebi:33386
Element-PaElement:PaUNII-0S6855V29MPa (element)Atomic ProtactiniumProtactinium element231Pa isotopeElement Protactinium
Database identifiers
- CAS
7440-13-3- PubChem CID
- 23945
- DTXSID
DTXSID50225387- ChEBI
CHEBI:33386- UNII
- 0S6855V29M
- EC Number
- 616-087-9
- Nikkaji
- J95.330J
Properties
Computed structural properties
- Topological polar surface area
- 0 Ų
- Hydrogen bond donors
- 0
- Hydrogen bond acceptors
- 0
- Rotatable bonds
- 0
- Heavy atoms
- 1
- Formal charge
- 0
- Complexity
- 0
Experimental & physicochemical properties
Chemical ClassesPhysical/Radiation -> Radionuclides
SpringerMaterials Propertieselectron density of states
Physical DescriptionShiny, silvery, malleable metal; All isotopes are radioactive; Pa-231 decays by alpha emission to Actinium-227; [Merck Index # 7883]
Physicochemical properties
- Melting point
- 1560 ° · 1560°
- Boiling point
- 4227 ° · bp 4227°
- Density
- 25 · d25 15.37
- form
- shiny metal
- color
- shiny metal; tetragonal or cubic
- Electrical Conductivity
- 5.6 · 5.6× 106S/m
- Thermal Conductivity
- 47 W/ · 47 W/(m·K)
- Specific Heat Capacity
- 0.1 J/ · Cp(gas): 0.1 J/(g·K), at 25℃
- FDA UNII
- 0 S6855V29M · 0S6855V29M
Safety & regulation
Safety information is for reference only and does not replace the supplier’s Safety Data Sheet (SDS), applicable regulations, or professional assessment.
Hazard information
Hazards Summary
Pa-231 decays to Actinium-227 by emitting an alpha particle. Actinium-227 and its decay products account for more than 80% of the inhalation hazard associated with exposure to Pa-231. [Argonne] Most Important Radionuclide: Pa-231 Source: Uranium ores; Half-Life: 33,000 years Specific Activity: 0.048 Ci/g Decay Mode: Alpha GI Absorption: 0.05% Lung Clearance Half-Time: Years for oxides and hydroxides; Weeks for all other compounds; Internal Toxicity: Very High Annual Limit on Intake: 0.000002 mCi Average Radiation Energy (MeV): Alpha 5.0; Beta 0.065; Gamma 0.048 [Argonne] [See Glossary for references.] See Radiation, ionizing.
Chemistry & industry
Pharmacology
Biological Half-LifeBiological half life: 50 years (skeleton); 10 days (liver); 10 days to 60 days (kidneys); [ANL Radiological Fact Sheets]
Uses & manufacturing
Uses
Used in scientific research with no commercial uses; It is present in uranium ores at a concentration of 1 part proactinium per 3 million parts uranium. Of the 20 known isotopes, 3 are naturally occurring: Pa-231, Pa-234, and Pa-234m with half lives of 33,000 years, 6.7 hours, and 1.2 minutes, respectively. [Argonne]
Applications
HistoryIn 1913 Fajans and Gohring identified the first isotope of this element, a metastable isotope having a mass 234, Pa-234m, a short-lived member of uranium-238 decay series. They named it brevium. In 1918, two independent groups, namely Hahn and Meitner and Soddy, Cranston, and Fleck simultaneously identified a longer-lived isotope Pa-231, a member of the uranium-235 decay series. The isotope Pa-234 in its ground state was discovered by Hahn and Meitner in 1921. The element derived its name from the Greek word protos, which means ‘first.’ Protactinium 231 occurs in the ore pitchblende at about 0.1ppm abundance. Certain ores of pitchblende have a higher abundance of this isotope, about 3ppm. Pa-231 also is found naturally in uranium and radium wastes. No commercial application of protactinium isotopes is known.
Uses233Pa as intermediate in production of fissile 233U in thorium breeder reactors.
Upstream & downstream products
Upstream raw materials
Additional notes
ChEBI: Protactinium atom is an actinoid atom and a f-block element atom.
Related reactions
0 records
No reaction records under the current filter.
Compound notes
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