{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.caesium","code":"thing-q1108","url":"https://ver.cy/models/thing/q1108/","name":"caesium","alternateNames":["caesium-137","caesium-129","caesium-135","caesium-116m","caesium-117m","caesium-118m","caesium-119m","caesium-120m","caesium-121m","caesium-122m1","caesium-122m2","caesium-122m3"],"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 fifty-five, a soft, gold-coloured alkali metal that melts near room temperature and reacts violently with water, with one stable isotope, caesium-133, whose hyperfine transition defines the second, and radioactive isotopes such as caesium-137, a fission product of concern in nuclear accidents and used in industrial and medical sources, and caesium-135; caesium is used in atomic clocks, drilling fluids, photoelectric cells and research, and is described here without handling or acquisition detail for radioactive sources.","purpose":"Let an agent explain caesium as an element and its properties and isotopes, describe its role in timekeeping and industry, relay radiological information on caesium-137 with reference to authorities, and decline handling or acquisition detail for radioactive sources.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Most reactive stable metal","Atomic clock standard","Caesium-137 fission product","Low melting point"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What caesium is.","layers":[{"id":"element","name":"Element","description":"The element.","findings":[{"id":"element-finding","name":"Element","description":"Element.","questions":[{"text":"What are the properties, occurrence and chemistry of caesium?","kind":"definition"},{"text":"Is the request seeking handling or acquisition detail for radioactive sources, 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 caesium exist, and why are caesium-133 and caesium-137 important?","kind":"definition"},{"text":"Which entry fits radioisotopes?","kind":"action"}]}]}]},{"id":"use","name":"Use","description":"Uses.","layers":[{"id":"clocks","name":"Clocks","description":"Atomic clocks.","findings":[{"id":"clocks-finding","name":"Clocks","description":"Clocks.","questions":[{"text":"How does the caesium-133 transition define the second, and how do caesium atomic clocks work?","kind":"definition"},{"text":"Which entry fits atomic clocks?","kind":"action"}]}]},{"id":"industry","name":"Industry","description":"Industrial uses.","findings":[{"id":"industry-finding","name":"Industry","description":"Industry.","questions":[{"text":"How is caesium used in drilling fluids, photoelectric devices and research?","kind":"provenance"},{"text":"Which entry fits a specific application?","kind":"action"}]}]}]},{"id":"radiological","name":"Radiological","description":"Caesium-137 and safety.","layers":[{"id":"releases","name":"Releases","description":"Environmental releases.","findings":[{"id":"releases-finding","name":"Releases","description":"Releases.","questions":[{"text":"How has caesium-137 been released in nuclear accidents and tests, and how does it behave in the environment, according to authorities?","kind":"provenance"},{"text":"Is a radiological emergency present now, requiring official instructions?","kind":"boundary"}]}]},{"id":"protection","name":"Protection","description":"Protection.","findings":[{"id":"protection-finding","name":"Protection","description":"Protection.","questions":[{"text":"What do radiation protection authorities say about caesium-137 exposure and food safety?","kind":"provenance"},{"text":"Which entry fits radiation protection?","kind":"action"}]}]}]},{"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 caesium discovered by spectroscopy, and how did it become the time standard?","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 caesium illustrate alkali metal chemistry and metrology safely?","kind":"action"},{"text":"Which misconceptions arise?","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Explain caesium's properties and its role in atomic clocks and the definition of the second.","State that radioactive caesium sources are strictly regulated and point to radiation authorities."],"mustNot":["Give information on obtaining, extracting or handling radioactive caesium sources.","Assist in using radioactive material to harm people or contaminate places.","Advise on handling caesium metal outside a qualified laboratory.","Downplay contamination risks after a radiation incident."],"requiresHuman":["Any request about possessing, moving or disposing of a radioactive source."]},"ethics":{"considerations":["Lost caesium sources have caused deadly contamination in communities.","Accurate information in radiation emergencies protects the public."],"affectedParties":["The public","Scrap and waste workers","Emergency responders"]},"owners":{"steward":"The licensed holder of a source; nuclear regulators control possession.","roles":[],"masterSystems":["National registers of licensed radioactive sources"]},"relations":[{"target":"Q19557","type":"parent","note":"registry parent class"},{"target":"Q208106","type":"parent","note":"registry parent class"},{"target":"Q428766","type":"parent","note":"registry parent class"},{"target":"alkali metal","type":"related","note":"category"},{"target":"light metal","type":"related","note":"category"},{"target":"polonium","type":"related","note":"another radioactive element entry"},{"target":"nuclear fission","type":"related","note":"source of caesium-137"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.caesium","Wikidata: Q1108 (https://www.wikidata.org/wiki/Q1108)"]},"properties":{"applicability":"required","items":["Melting temperature: Approximately 28.4 degrees Celsius - This approximate value applies to pure elemental caesium near standard atmospheric pressure.","Boiling temperature: Approximately 671 degrees Celsius - This approximate value applies to pure elemental caesium at standard atmospheric pressure.","Mass density: Approximately 1.9 grams per cubic centimetre - This approximate value describes solid elemental caesium near room temperature."]},"recognition":{"applicability":"required","items":["Atomic number fifty-five","Defines the second through caesium-133","Rubidium and francium are neighbouring alkali metals","A soft gold-coloured metal, liquid near room temperature."]},"capabilities":{"applicability":"required","items":["explain the element and isotopes","describe timekeeping and industrial uses","relay radiological information","decline source handling detail"]},"hazards":{"applicability":"required","items":["Providing handling or acquisition detail for radioactive sources, which must be declined","Fire and explosion from reaction with water","Contamination from caesium-137 releases"]},"interfaces":{"applicability":"required","items":["SI definition of the second","Radiation protection and radioactive source control","Chemical safety regulations for reactive metals"]},"context":{"applicability":"required","items":["Element fifty-five, an alkali metal.","caesium metal and compounds","caesium-133 and the definition of the second","caesium-137 and other radioisotopes","caesium in drilling fluids and industry","caesium in research and photoelectric devices"]}},"sources":[{"title":"Wikidata item Q1108: caesium","url":"https://www.wikidata.org/wiki/Q1108","note":"identity and sense of the item"},{"title":"Wikipedia: Caesium","url":"https://en.wikipedia.org/wiki/Caesium","note":"general description of the item"}],"openQuestions":["Should caesium-137 be a separate entry?","How should radiation authorities be linked?","How should metrology resources be linked?"],"resources":{"spec":"/models/things/publications/thing-q1108/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q1108/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T03:49:29Z","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 2026-10-07T12:16:28+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}