{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.astatine","code":"thing-q999","url":"https://ver.cy/models/thing/q999/","name":"astatine","alternateNames":["astatine-191","astatine-191m","astatine-193","astatine-193m1","astatine-193m2","astatine-194","astatine-194m","astatine-195","astatine-195m","astatine-196","astatine-196m1","astatine-196m2"],"kind":"thing","status":"published","version":"0.2.0-wave.2","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.MAT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"The chemical element with atomic number eighty-five, a halogen lighter than tennessine and the rarest naturally occurring element, existing only in trace amounts from decay of heavier elements and in short-lived radioactive isotopes such as astatine-210 and astatine-211, whose properties are inferred from tiny quantities and theory, and which shows both halogen and metallic character; astatine-211 is studied for targeted alpha therapy in cancer, and the element is described here without handling or production detail.","purpose":"Let an agent explain astatine as an element and its rarity and properties, describe its isotopes and medical research use, present what is known and uncertain with attribution, and decline production or handling detail for radioactive material.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Extreme rarity","Short-lived isotopes","Halogen and metallic character","Medical research isotope"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What astatine is.","layers":[{"id":"element","name":"Element","description":"The element.","findings":[{"id":"element-finding","name":"Element","description":"Element.","questions":[{"text":"What is known about astatine properties, and why is so little known?","kind":"definition"},{"text":"Is the request seeking production or handling detail, which must be declined?","kind":"boundary"}]}]},{"id":"isotopes","name":"Isotopes","description":"Isotopes.","findings":[{"id":"isotopes-finding","name":"Isotopes","description":"Isotopes.","questions":[{"text":"What isotopes of astatine exist, and how do they arise in nature and in accelerators?","kind":"definition"},{"text":"Which entry fits radioisotopes?","kind":"action"}]}]}]},{"id":"research","name":"Research","description":"Research and medicine.","layers":[{"id":"medicine","name":"Medicine","description":"Targeted alpha therapy.","findings":[{"id":"medicine-finding","name":"Medicine","description":"Medicine.","questions":[{"text":"How is astatine-211 studied for targeted alpha therapy, and what is the evidence status, with findings attributed?","kind":"provenance"},{"text":"Is the user asking about their own treatment, which needs a clinician?","kind":"boundary"}]}]},{"id":"chemistry","name":"Chemistry","description":"Chemistry at trace level.","findings":[{"id":"chemistry-finding","name":"Chemistry","description":"Chemistry.","questions":[{"text":"How do chemists study astatine chemistry with tiny quantities, and what uncertainties remain?","kind":"provenance"},{"text":"Which findings are uncertain?","kind":"boundary"}]}]}]},{"id":"learn","name":"Learn","description":"History and teaching.","layers":[{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How was astatine synthesised and named, and how did earlier claims of discovery fare?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"teach","name":"Teach","description":"Teaching.","findings":[{"id":"teach-finding","name":"Teach","description":"Teaching.","questions":[{"text":"How can astatine illustrate periodic trends and radioactivity?","kind":"action"},{"text":"Which misconceptions arise?","kind":"provenance"}]}]}]},{"id":"context","name":"Context","description":"Periodic context.","layers":[{"id":"halogens","name":"Halogens","description":"Place among halogens.","findings":[{"id":"halogens-finding","name":"Halogens","description":"Halogens.","questions":[{"text":"How does astatine compare with the other halogens and with metals?","kind":"definition"},{"text":"Which entry fits halogens?","kind":"action"}]}]},{"id":"rarity","name":"Rarity","description":"Rarity.","findings":[{"id":"rarity-finding","name":"Rarity","description":"Rarity.","questions":[{"text":"How much astatine exists on Earth at any time, and how is this estimated?","kind":"provenance"},{"text":"Which entry fits natural radioactivity?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Report astatine's properties, isotopes and research uses from scientific sources.","Explain why astatine is so scarce and short-lived."],"mustNot":["Help anyone obtain, produce or handle astatine outside a licensed facility.","Assist in using radioactive materials to harm people.","Present its medical uses in research as approved treatments where they are not."],"requiresHuman":["Any decision on radiation exposure of patients or workers in research."]},"ethics":{"considerations":["Radioactive substances endanger health and require strict control.","Experimental radiotherapies raise questions of consent and fair access."],"affectedParties":["Patients in trials","Radiation workers"]},"owners":{"steward":"Licensed nuclear and research facilities under the radiation safety regulator.","roles":[],"masterSystems":["Radioactive source and licence registers"]},"relations":[{"target":"Q19596","type":"parent","note":"registry parent class"},{"target":"Q19605","type":"parent","note":"registry parent class"},{"target":"halogens","type":"related","note":"category"},{"target":"metalloid","type":"related","note":"category"},{"target":"iodine","type":"related","note":"the lighter halogen"},{"target":"polonium","type":"related","note":"a neighbouring radioactive element"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.astatine","Wikidata: Q999 (https://www.wikidata.org/wiki/Q999)"]},"properties":{"applicability":"required","items":["Atomic number: 85 dimensionless - Every astatine nucleus contains exactly 85 protons.","Radioactive half-life of astatine-210: Approximately 8.1 h - This isotope-specific value describes the time for half the nuclei in a population to decay.","Radioactive half-life of astatine-211: Approximately 7.2 h - This isotope-specific value describes the time for half the nuclei in a population to decay."]},"recognition":{"applicability":"required","items":["Atomic number eighty-five","Radioactive halogen","Iodine is the stable lighter halogen; tennessine is the heavier synthetic element","Never seen in bulk; predicted to be a dark solid."]},"capabilities":{"applicability":"required","items":["explain the element and rarity","describe isotopes and research","present uncertainties","decline handling detail"]},"hazards":{"applicability":"required","items":["Providing production or handling detail, which must be declined","Overstating known properties","Agents giving personal advice on experimental therapy"]},"interfaces":{"applicability":"required","items":["Radiation protection rules for radioactive materials","Regulation of radiopharmaceutical research","Chemical nomenclature"]},"context":{"applicability":"required","items":["Element eighty-five, the rarest halogen.","naturally occurring trace astatine","astatine-211","astatine-210 and other isotopes","astatine compounds studied at trace level","astatine in targeted alpha therapy research"]}},"sources":[{"title":"Wikidata item Q999: astatine","url":"https://www.wikidata.org/wiki/Q999","note":"identity and sense of the item"},{"title":"Wikipedia: Astatine","url":"https://en.wikipedia.org/wiki/Astatine","note":"general description of the item"}],"openQuestions":["Should astatine-211 be a separate entry?","How should radiochemistry resources be linked?","How should clinical trial registries be linked?"],"resources":{"spec":"/models/things/publications/thing-q999/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q999/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T04:43:14Z","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 2026-10-07T12:16:35+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}