{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.gadolinium","code":"thing-q1832","url":"https://ver.cy/models/thing/q1832/","name":"gadolinium","alternateNames":["gadolinium-166","gadolinium-167","gadolinium-134","gadolinium-135","gadolinium-136","gadolinium-137","gadolinium-138","gadolinium-138m","gadolinium-139","gadolinium-139m","gadolinium-140","gadolinium-141"],"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 Gd and atomic number 64, a silvery lanthanide with the highest thermal neutron capture cross-section of any stable element, ferromagnetic below room temperature, obtained from monazite and bastnasite and used in gadolinium-based contrast agents for magnetic resonance imaging, in neutron shielding and reactor control, in magnetic refrigeration research, in phosphors and in alloys; gadolinium has six stable isotopes plus the very long-lived gadolinium-152, with radioactive isotopes from gadolinium-134 upward.","purpose":"Let an agent identify gadolinium and its properties, relay isotopes, production and uses from reference sources, describe MRI contrast agents and their safety in general terms, and distinguish gadolinium from neighbouring lanthanides.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Highest neutron capture","Room-temperature Curie point","MRI contrast use","Magnetocaloric effect"],"structure":{"bundles":[{"id":"identify","name":"Identify","description":"What gadolinium is.","layers":[{"id":"properties","name":"Properties","description":"Properties.","findings":[{"id":"properties-finding","name":"Properties","description":"Properties.","questions":[{"text":"What are the physical, magnetic and nuclear properties of gadolinium?","kind":"definition"},{"text":"Is the question about gadolinium or a neighbouring lanthanide?","kind":"boundary"}]}]},{"id":"isotopes","name":"Isotopes","description":"Isotopes.","findings":[{"id":"isotopes-finding","name":"Isotopes","description":"Isotopes.","questions":[{"text":"Which isotopes exist, and which have high neutron capture?","kind":"definition"},{"text":"Which entry fits the specific isotope?","kind":"action"}]}]}]},{"id":"source","name":"Source","description":"Occurrence and production.","layers":[{"id":"occurrence","name":"Occurrence","description":"Occurrence.","findings":[{"id":"occurrence-finding","name":"Occurrence","description":"Occurrence.","questions":[{"text":"Where does gadolinium occur, and how is it separated?","kind":"provenance"},{"text":"Which entry fits rare earth mining?","kind":"action"}]}]},{"id":"supply","name":"Supply","description":"Supply.","findings":[{"id":"supply-finding","name":"Supply","description":"Supply.","questions":[{"text":"Who produces gadolinium, and how is it traded, with sources?","kind":"measurement"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]},{"id":"use","name":"Use","description":"Uses.","layers":[{"id":"medical","name":"Medical","description":"MRI contrast.","findings":[{"id":"medical-finding","name":"Medical","description":"Medical.","questions":[{"text":"How do gadolinium contrast agents work, and what safety issues have regulators addressed, in general terms?","kind":"provenance"},{"text":"Is the user asking about their own scan, which needs a clinician?","kind":"boundary"}]}]},{"id":"other","name":"Other","description":"Nuclear, magnetic and other uses.","findings":[{"id":"other-finding","name":"Other","description":"Other.","questions":[{"text":"How is gadolinium used in neutron shielding, magnetic refrigeration and phosphors?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]}]},{"id":"context","name":"Context","description":"History and environment.","layers":[{"id":"discovery","name":"Discovery","description":"Discovery.","findings":[{"id":"discovery-finding","name":"Discovery","description":"Discovery.","questions":[{"text":"How was gadolinium discovered by Marignac in 1880 and named after Johan Gadolin?","kind":"provenance"},{"text":"Which entry fits the history of the rare earths?","kind":"action"}]}]},{"id":"environment","name":"Environment","description":"Environmental gadolinium.","findings":[{"id":"environment-finding","name":"Environment","description":"Environment.","questions":[{"text":"What do studies report about anthropogenic gadolinium in rivers from medical use?","kind":"provenance"},{"text":"Which entry fits pharmaceutical pollution?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Describe gadolinium's properties and uses in imaging, nuclear and magnetic technology.","Report safety data sheets and handling rules for gadolinium compounds."],"mustNot":["Advise on contrast agent doses or use for a patient in place of a clinician.","Downplay concerns about gadolinium retention or kidney-related risks from contrast agents.","Recommend disposal of gadolinium waste outside approved routes.","Misstate the source or sustainability of rare earth supply."],"requiresHuman":["Deciding to give a gadolinium contrast agent to a patient with kidney disease."]},"ethics":{"considerations":["Contrast agents help diagnosis but carry risks patients deserve to be told about.","Rare earth mining causes pollution that falls on local communities."],"affectedParties":["Patients","Communities near rare earth mines","Workers"]},"owners":{"steward":"The holder of the material; regulators for medical products and chemicals.","roles":[],"masterSystems":["Chemical substance inventories","Medicines regulators' product registers"]},"relations":[{"target":"Q105789","type":"parent","note":"registry parent class"},{"target":"Q19569","type":"parent","note":"registry parent class"},{"target":"lanthanide","type":"related","note":"in registry terms"},{"target":"heavy metal","type":"related","note":"in registry terms"},{"target":"gadolinium-based contrast agent","type":"related","note":"for MRI"},{"target":"terbium","type":"related","note":"element 65"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.gadolinium","Wikidata: Q1832 (https://www.wikidata.org/wiki/Q1832)","symbol: Gd","CAS: 7440-54-2"]},"properties":{"applicability":"required","items":["atomic number: 64 Z","standard atomic weight: 157.25 u","Curie temperature: about 20 degrees C","thermal neutron cross-section: about 49000 barns - natural mixture"]},"recognition":{"applicability":"required","items":["Element 64, symbol Gd","Lanthanide of MRI contrast and neutron capture","Europium and terbium are the neighbouring lanthanides","A silvery metal that tarnishes slowly in dry air."]},"capabilities":{"applicability":"required","items":["relay properties and isotopes","explain production and uses","describe contrast agent safety in general terms","distinguish from other lanthanides"]},"hazards":{"applicability":"required","items":["Nephrogenic systemic fibrosis with some agents in kidney disease","Gadolinium retention and environmental release","Confusing with neighbouring lanthanides"]},"interfaces":{"applicability":"required","items":["Drug regulation of gadolinium contrast agents, including restrictions on linear agents","Chemical safety data sheets","Nuclear material rules for neutron absorbers"]},"context":{"applicability":"required","items":["MRI contrast, neutron capture, magnets and phosphors.","gadolinium metal and alloys","gadolinium compounds and chelates for MRI","stable isotopes from gadolinium-154 to gadolinium-160 and the long-lived gadolinium-152","radioactive isotopes such as gadolinium-134 to gadolinium-137 and gadolinium-166 and 167","gadolinium in phosphors and garnets"]}},"sources":[{"title":"Wikidata item Q1832: gadolinium","url":"https://www.wikidata.org/wiki/Q1832","note":"identity and sense of the item"},{"title":"Wikipedia: Gadolinium","url":"https://en.wikipedia.org/wiki/Gadolinium","note":"general description of the item"}],"openQuestions":["Should gadolinium contrast agent be a separate primary entry?","How should reference and regulatory sources be linked?","The registry entry has merged aliases naming isotopes; should they be split off?"],"resources":{"spec":"/models/things/publications/thing-q1832/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q1832/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T01:30:35Z","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 2026-10-06T19:51:55+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}