{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.francium","code":"thing-q671","url":"https://ver.cy/models/thing/q671/","name":"francium","alternateNames":["francium-199","francium-200","francium-200m","francium-201","francium-202","francium-202m","francium-203","francium-204","francium-204m1","francium-204m2","francium-205","francium-206"],"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 highly radioactive alkali metal, chemical element 87, the heaviest member of group 1 and one of the rarest naturally occurring elements, formed in trace amounts by decay of actinium; its longest-lived isotope, francium-223, has a half-life of about 22 minutes, so it has no practical uses beyond research in atomic physics and spectroscopy.","purpose":"Let an agent explain francium as an element, relay its properties, occurrence and research uses from reference sources, and separate fact from popular exaggeration about its reactivity and quantity.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Heaviest alkali metal","No stable isotopes","Trace natural occurrence in uranium ores","Studied as trapped atoms"],"structure":{"bundles":[{"id":"element","name":"Element","description":"What francium is.","layers":[{"id":"properties","name":"Properties","description":"Properties and isotopes.","findings":[{"id":"properties-finding","name":"Properties","description":"Properties.","questions":[{"text":"What are the known and predicted properties of francium, and what isotopes exist?","kind":"definition"},{"text":"Is the question about the element or about popular claims that need correction?","kind":"boundary"}]}]},{"id":"occurrence","name":"Occurrence","description":"Occurrence and production.","findings":[{"id":"occurrence-finding","name":"Occurrence","description":"Occurrence.","questions":[{"text":"How does francium occur naturally, and how is it produced for research?","kind":"provenance"},{"text":"Which entry fits actinium?","kind":"action"}]}]}]},{"id":"research","name":"Research","description":"Scientific use.","layers":[{"id":"experiments","name":"Experiments","description":"Trapped atom experiments.","findings":[{"id":"experiments-finding","name":"Experiments","description":"Experiments.","questions":[{"text":"How is francium studied in atom traps, and what questions do experiments address?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"limits","name":"Limits","description":"What cannot be done.","findings":[{"id":"limits-finding","name":"Limits","description":"Limits.","questions":[{"text":"Why can francium not be studied in bulk, and what follows for claims about it?","kind":"provenance"},{"text":"Which entry fits radioactive decay?","kind":"action"}]}]}]},{"id":"safety","name":"Safety","description":"Radiation.","layers":[{"id":"radiation","name":"Radiation","description":"Radiation hazard.","findings":[{"id":"radiation-finding","name":"Radiation","description":"Radiation.","questions":[{"text":"What radiation protection rules apply to research with francium?","kind":"provenance"},{"text":"Which entry fits radiation protection?","kind":"action"}]}]},{"id":"handling","name":"Handling","description":"Handling.","findings":[{"id":"handling-finding","name":"Handling","description":"Handling.","questions":[{"text":"How are trace amounts handled in laboratories?","kind":"provenance"},{"text":"Is the question about a specific facility, which needs its safety officer?","kind":"boundary"}]}]}]},{"id":"context","name":"Context","description":"History and teaching.","layers":[{"id":"history","name":"History","description":"Discovery.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How did Marguerite Perey discover francium in 1939?","kind":"provenance"},{"text":"Which entry fits the discoverer?","kind":"action"}]}]},{"id":"teach","name":"Teach","description":"Teaching.","findings":[{"id":"teach-finding","name":"Teach","description":"Teaching.","questions":[{"text":"How is francium presented in teaching, and which misconceptions arise?","kind":"provenance"},{"text":"Which entry fits the periodic table?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Report francium's properties and isotopes from authoritative sources.","Explain why bulk properties of francium have never been observed."],"mustNot":["Present popular claims about francium's reactivity as observed fact.","Help obtain or handle radioactive material outside licensing and radiation protection rules.","Invent measured values for bulk francium.","Present francium as a practical material for ordinary uses."],"requiresHuman":["Approving research with radioactive sources."]},"ethics":{"considerations":["Radioactive materials need strict control to protect researchers and the public."],"affectedParties":["Researchers","The public"]},"owners":{"steward":"Nobody holds it in bulk; licensed laboratories answer for the traces they make.","roles":[],"masterSystems":[]},"relations":[{"target":"Q19557","type":"parent","note":"registry parent class"},{"target":"Q208106","type":"parent","note":"registry parent class"},{"target":"alkali metal","type":"related","note":"group 1"},{"target":"actinium","type":"related","note":"decay of actinium-227"},{"target":"caesium","type":"related","note":"the lighter homologue"},{"target":"atomic physics","type":"related","note":"trapped atom experiments"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.francium","Wikidata: Q671 (https://www.wikidata.org/wiki/Q671)","chemical symbol: Fr","CAS number: 7440-73-5"]},"properties":{"applicability":"required","items":["atomic number: 87","half-life of francium-223: about 22 minutes - longest-lived isotope","natural abundance: grams at any time in the crust estimate - often quoted as about 20-30 g"]},"recognition":{"applicability":"required","items":["Element 87, alkali metal","Extremely radioactive and short-lived","Caesium is the heaviest stable alkali metal","Never seen in bulk; expected to be a silvery metal, observed only as trapped atoms."]},"capabilities":{"applicability":"required","items":["explain properties and isotopes","explain occurrence and how it is made","relay research uses","correct common exaggerations"]},"hazards":{"applicability":"required","items":["Radiation hazard in research","Popular claims about explosive reactivity that cannot be tested in bulk","Confusing estimates of natural quantity"]},"interfaces":{"applicability":"required","items":["Radiation protection regulations for research handling"]},"context":{"applicability":"required","items":["Not for anything practical; a subject of atomic research.","francium-223 from actinium decay","synthetic isotopes made in accelerators","francium in atomic physics experiments"]}},"sources":[{"title":"Wikidata item Q671: francium","url":"https://www.wikidata.org/wiki/Q671","note":"identity and sense of the item"},{"title":"Wikipedia: Francium","url":"https://en.wikipedia.org/wiki/Francium","note":"general description of the item"}],"openQuestions":["Should isotopes be separate entries?","How should research references be linked?","The registry entry has merged isotope aliases; should they be split off?"],"resources":{"spec":"/models/things/publications/thing-q671/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q671/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T20:49:57Z","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 2026-10-06T19:52:01+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}