{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.protactinium","code":"thing-q1109","url":"https://ver.cy/models/thing/q1109/","name":"protactinium","alternateNames":["protactinium-212","protactinium-213","protactinium-214","protactinium-215","protactinium-216","protactinium-217","protactinium-218","protactinium-219","protactinium-220","protactinium-221","protactinium-222","protactinium-223"],"kind":"thing","status":"published","version":"0.2.0-wave.3","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.MAT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"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.","purpose":"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.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Rare actinide","Decay product of uranium","Thorium cycle intermediate","Highly toxic and radioactive"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What protactinium is.","layers":[{"id":"properties","name":"Properties","description":"Properties.","findings":[{"id":"properties-finding","name":"Properties","description":"Properties.","questions":[{"text":"What are the physical and chemical properties of protactinium?","kind":"definition"},{"text":"Is the question about the element, an isotope or a neighbouring actinide?","kind":"boundary"}]}]},{"id":"isotopes","name":"Isotopes","description":"Isotopes.","findings":[{"id":"isotopes-finding","name":"Isotopes","description":"Isotopes.","questions":[{"text":"What isotopes exist, and what are the roles of protactinium-231 and 233?","kind":"measurement"},{"text":"Which entry fits the specific isotope?","kind":"action"}]}]}]},{"id":"occur","name":"Occur","description":"Occurrence and chemistry.","layers":[{"id":"occurrence","name":"Occurrence","description":"Occurrence.","findings":[{"id":"occurrence-finding","name":"Occurrence","description":"Occurrence.","questions":[{"text":"Where does protactinium occur, and how is it isolated?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"chemistry","name":"Chemistry","description":"Chemistry.","findings":[{"id":"chemistry-finding","name":"Chemistry","description":"Chemistry.","questions":[{"text":"What is the chemistry of protactinium in its oxidation states?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]},{"id":"use","name":"Use","description":"Uses.","layers":[{"id":"nuclear","name":"Nuclear","description":"Thorium cycle.","findings":[{"id":"nuclear-finding","name":"Nuclear","description":"Nuclear.","questions":[{"text":"What role does protactinium-233 play in the thorium fuel cycle, in general terms?","kind":"provenance"},{"text":"Which entry fits thorium fuel cycle?","kind":"action"}]}]},{"id":"dating","name":"Dating","description":"Dating.","findings":[{"id":"dating-finding","name":"Dating","description":"Dating.","questions":[{"text":"How is protactinium-231 used in dating marine sediments?","kind":"provenance"},{"text":"Which entry fits uranium-thorium dating?","kind":"action"}]}]}]},{"id":"context","name":"Context","description":"Safety and history.","layers":[{"id":"safety","name":"Safety","description":"Safety.","findings":[{"id":"safety-finding","name":"Safety","description":"Safety.","questions":[{"text":"What are the hazards of protactinium, and how is it handled?","kind":"provenance"},{"text":"Which entry fits radiation protection?","kind":"action"}]}]},{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How was protactinium discovered by Fajans, Gohring, Hahn and Meitner?","kind":"provenance"},{"text":"Which entry fits the history of the periodic table?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Describe protactinium's properties and occurrence from scientific sources.","Explain its role in radiometric dating in general terms."],"mustNot":["Provide sensitive nuclear detail or methods for separating or concentrating it.","Advise handling radioactive material without licensed facilities.","Confuse protactinium with thorium or uranium in safety information."],"requiresHuman":["Any possession, transfer or experiment involving radioactive material."]},"ethics":{"considerations":["Radioactive materials can harm workers and the public if mishandled.","Nuclear information is controlled to prevent misuse."],"affectedParties":["Laboratory workers","The public","Students"]},"owners":{"steward":"The licensed holder, under the national nuclear regulator.","roles":[],"masterSystems":["National registers of radioactive sources and materials"]},"relations":[{"target":"Q105789","type":"parent","note":"registry parent class"},{"target":"Q19577","type":"parent","note":"registry parent class"},{"target":"actinide","type":"related","note":"in registry terms"},{"target":"heavy metal","type":"related","note":"in registry terms"},{"target":"thorium fuel cycle","type":"related","note":"as protactinium-233"},{"target":"uranium-235","type":"related","note":"via actinium series"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.protactinium","Wikidata: Q1109 (https://www.wikidata.org/wiki/Q1109)","CAS: 7440-13-3 protactinium","symbol: Pa element"]},"properties":{"applicability":"required","items":["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"]},"recognition":{"applicability":"required","items":["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","A bright silvery metal that tarnishes in air."]},"capabilities":{"applicability":"required","items":["explain properties and isotopes","relay occurrence and chemistry","describe research uses","distinguish from neighbouring elements"]},"hazards":{"applicability":"required","items":["Radiotoxicity","Confusing with thorium or uranium","Agents providing sensitive nuclear detail"]},"interfaces":{"applicability":"required","items":["Radiation protection and nuclear material controls","Laboratory safety rules for actinides"]},"context":{"applicability":"required","items":["Research; intermediate in the thorium fuel cycle.","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"]}},"sources":[{"title":"Wikidata item Q1109: protactinium","url":"https://www.wikidata.org/wiki/Q1109","note":"identity and sense of the item"},{"title":"Wikipedia: Protactinium","url":"https://en.wikipedia.org/wiki/Protactinium","note":"general description of the item"}],"openQuestions":["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?"],"resources":{"spec":"/models/things/publications/thing-q1109/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q1109/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T06:11:31Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:51:53+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}