protactinium
Let an agent explain protactinium as an element, relay its isotopes, occurrence and chemistry from chemistry references, describe its role in the thorium fuel cycle and dating in general terms, and distinguish protactinium from thorium, uranium and neighbouring actinides.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent explain protactinium as an element, relay its isotopes, occurrence and chemistry from chemistry references, describe its role in the thorium fuel cycle and dating in general terms, and distinguish protactinium from thorium, uranium and neighbouring actinides.
A chemical element with symbol Pa and atomic number 91, a dense, silvery radioactive actinide metal occurring in trace amounts in uranium ores as a decay product, with protactinium-231 the longest-lived isotope at about 32700 years and protactinium-233 an intermediate in the thorium fuel cycle, together with short-lived isotopes such as protactinium-212 to 217 known from experiments; protactinium has no significant uses beyond research and is highly toxic and radioactive, so it is handled only in specialised laboratories.
What it is for: Research; intermediate in the thorium fuel cycle.
It can be explain properties and isotopes; relay occurrence and chemistry; describe research uses; distinguish from neighbouring elements.
Distinguishing features
Rare actinide
Decay product of uranium
Thorium cycle intermediate
Highly toxic and radioactive
What it looks like
A bright silvery metal that tarnishes in air.
Physical character
atomic number: 91 Z
density: about 15.4 g/cm^3
protactinium-231 half-life: about 32760 years
crustal abundance: trace note - from uranium decay
How it is recognised
Radioactive actinide between thorium and uranium
Protactinium-231 and 233; short-lived isotopes 212 to 217 and others
Thorium is element 90; uranium is element 92
Related models
is a kind of - in registry terms
is a kind of - in registry terms
is produced in - as protactinium-233
decays from - via actinium series
In practice
Families and kinds
protactinium-231 in uranium ores
protactinium-233 in the thorium fuel cycle
short-lived isotopes such as protactinium-212 to 217
protactinium compounds in the +4 and +5 states
Identifiers
CAS 7440-13-3 protactinium
symbol Pa element
Standards and regulation
Radiation protection and nuclear material controls
Laboratory safety rules for actinides
Failure modes and hazards
Radiotoxicity
Confusing with thorium or uranium
Agents providing sensitive nuclear detail
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.protactinium
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Understand What protactinium is.
Science.
Properties
Properties.
Properties
Properties.
- What are the physical and chemical properties of protactinium? definition
- Is the question about the element, an isotope or a neighbouring actinide? boundary
Isotopes
Isotopes.
Isotopes
Isotopes.
- What isotopes exist, and what are the roles of protactinium-231 and 233? measurement
- Which entry fits the specific isotope? action
Occur Occurrence and chemistry.
Science.
Occurrence
Occurrence.
Occurrence
Occurrence.
- Where does protactinium occur, and how is it isolated? provenance
- Which references are standard? provenance
Chemistry
Chemistry.
Chemistry
Chemistry.
- What is the chemistry of protactinium in its oxidation states? provenance
- Which sources are cited? provenance
Use Uses.
Application.
Nuclear
Thorium cycle.
Nuclear
Nuclear.
- What role does protactinium-233 play in the thorium fuel cycle, in general terms? provenance
- Which entry fits thorium fuel cycle? action
Dating
Dating.
Dating
Dating.
- How is protactinium-231 used in dating marine sediments? provenance
- Which entry fits uranium-thorium dating? action
Context Safety and history.
Context.
Safety
Safety.
Safety
Safety.
- What are the hazards of protactinium, and how is it handled? provenance
- Which entry fits radiation protection? action
History
History.
History
History.
- How was protactinium discovered by Fajans, Gohring, Hahn and Meitner? provenance
- Which entry fits the history of the periodic table? action
What the second pass must settle
- Should isotopes of protactinium be a separate entry?
- How should chemistry references be linked?
- The registry entry has merged aliases naming individual isotopes; should they be split off?