{ "model": { "rank": 13003, "code": "thing-q13533728", "model_id": "vr.tr.double-displacement-reaction", "name": "double displacement reaction", "purpose": "Let an agent explain double displacement reactions and their pattern, relay salt metathesis, driving forces and demonstrations from chemistry references, describe olefin metathesis as a related but distinct reaction, and distinguish double displacement from single displacement, acid-base and redox reactions.", "family": "Thing Registry", "category": "Activities and processes", "status": "research-draft", "kind": "thing", "plane": "ACT", "domain": "ACT.PRC", "industry": "", "version": "", "url": "/models/thing/q13533728/", "tier": 2, "score": 38, "payload": { "layer": "wikidata", "aliases": [ "golden rain demonstration", "Salt metathesis reaction", "olefin metathesis" ], "aliasCount": 3, "merged": 3, "knownIn": 38, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": null, "source": { "dataset": "wikidata", "item": "Q13533728", "url": "https://www.wikidata.org/wiki/Q13533728", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-13T13:48:29Z", "providers": [ "Claude" ], "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify", "pass": 2, "wave": 4, "engine": "claude" }, "metaModel": { "id": "THING-Q13533728", "registryId": "vr.tr.double-displacement-reaction", "name": "double displacement reaction", "version": "0.2.0-wave.4", "entryKind": "thing", "family": "Thing Registry", "domain": [ "ACT.PRC" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q13533728/", "model": { "registry_id": "vr.tr.double-displacement-reaction", "name": "double displacement reaction", "purpose": "Let an agent explain double displacement reactions and their pattern, relay salt metathesis, driving forces and demonstrations from chemistry references, describe olefin metathesis as a related but distinct reaction, and distinguish double displacement from single displacement, acid-base and redox reactions.", "definition": "A chemical reaction in which two compounds exchange partners to form two new compounds, following the pattern AB plus CD gives AD plus CB, most commonly as salt metathesis in solution producing a precipitate, gas or water, as in the golden rain demonstration that forms lead iodide crystals, and by extension the olefin metathesis of organic chemistry in which alkene fragments are exchanged with catalysts; double displacement reactions are staple examples in chemistry education.", "what_it_is_for": "Not applicable; a reaction class.", "affordances": [ "explain the pattern", "relay examples and demonstrations", "describe olefin metathesis", "distinguish related reactions" ], "distinguishing_features": [ "Partner exchange", "Precipitation driving force", "Teaching staple", "Organic extension" ], "appearance": "Not a visible object; often a precipitate forming in solution.", "visual_identification": [ "Exchange of partners between two compounds", "Salt metathesis, precipitation, golden rain, olefin metathesis", "Single displacement replaces one element; acid-base transfers protons; redox transfers electrons" ], "physical_properties": [ { "quantity": "pattern", "typical_range": "AB + CD gives AD + CB", "unit": "formula", "note": "" }, { "quantity": "golden rain", "typical_range": "lead nitrate and potassium iodide", "unit": "note", "note": "lead iodide precipitate" }, { "quantity": "olefin metathesis Nobel Prize", "typical_range": "2005", "unit": "year", "note": "Chauvin, Grubbs, Schrock" } ], "families_and_kinds": [ "precipitation reactions", "gas-forming double displacements", "neutralisation as a special case", "salt metathesis in synthesis", "olefin metathesis as a distinct catalytic reaction", "classroom demonstrations such as golden rain" ], "related_models": [ { "relation": "is a kind of", "target": "chemical reaction", "why": "in registry terms" }, { "relation": "is exemplified by", "target": "precipitation reaction", "why": "in solution" }, { "relation": "is contrasted with", "target": "single displacement reaction", "why": "replacing one element" }, { "relation": "is related to", "target": "olefin metathesis", "why": "a catalytic organic reaction" } ], "identifiers": [], "standards_and_regulation": [ "Laboratory safety rules for demonstrations, including lead compounds", "IUPAC nomenclature" ], "failure_modes_and_hazards": [ "Toxic reagents in demonstrations such as lead salts", "Confusing double displacement with other reaction types", "Registry alias olefin metathesis is a distinct reaction" ], "in_scope": [], "out_of_scope": [], "characteristics": [] }, "sources": [], "structure": { "bundles": [ { "id": "understand", "name": "Understand", "description": "What a double displacement reaction is.", "rationale": "Science.", "layers": [ { "id": "definition", "name": "Definition", "description": "Definition.", "findings": [ { "id": "definition-finding", "name": "Definition", "description": "Definition.", "questions": [ { "text": "What is a double displacement reaction, and how does it differ from single displacement, acid-base and redox reactions?", "kind": "definition" }, { "text": "Is the question about the general pattern, an example, a demonstration or olefin metathesis?", "kind": "boundary" } ] } ] }, { "id": "driving", "name": "Driving", "description": "Driving forces.", "findings": [ { "id": "driving-finding", "name": "Driving", "description": "Driving.", "questions": [ { "text": "Why do these reactions proceed, through precipitate, gas or water formation?", "kind": "definition" }, { "text": "Which entry fits solubility rules?", "kind": "action" } ] } ] } ] }, { "id": "examples", "name": "Examples", "description": "Examples.", "rationale": "Practice.", "layers": [ { "id": "demonstrations", "name": "Demonstrations", "description": "Demonstrations.", "findings": [ { "id": "demonstrations-finding", "name": "Demonstrations", "description": "Demonstrations.", "questions": [ { "text": "How does the golden rain demonstration work, and what safety measures apply?", "kind": "provenance" }, { "text": "Which references are standard?", "kind": "provenance" } ] } ] }, { "id": "synthesis", "name": "Synthesis", "description": "Synthesis.", "findings": [ { "id": "synthesis-finding", "name": "Synthesis", "description": "Synthesis.", "questions": [ { "text": "How is salt metathesis used in inorganic and organometallic synthesis?", "kind": "provenance" }, { "text": "Which sources are cited?", "kind": "provenance" } ] } ] } ] }, { "id": "organic", "name": "Organic", "description": "Olefin metathesis.", "rationale": "Science.", "layers": [ { "id": "mechanism", "name": "Mechanism", "description": "Mechanism.", "findings": [ { "id": "mechanism-finding", "name": "Mechanism", "description": "Mechanism.", "questions": [ { "text": "How does olefin metathesis exchange alkene fragments, and what catalysts are used?", "kind": "provenance" }, { "text": "Which entry fits olefin metathesis?", "kind": "action" } ] } ] }, { "id": "applications", "name": "Applications", "description": "Applications.", "findings": [ { "id": "applications-finding", "name": "Applications", "description": "Applications.", "questions": [ { "text": "How is olefin metathesis used in polymers and pharmaceuticals?", "kind": "provenance" }, { "text": "Which entry fits Grubbs catalyst?", "kind": "action" } ] } ] } ] }, { "id": "context", "name": "Context", "description": "Teaching and history.", "rationale": "Context.", "layers": [ { "id": "teaching", "name": "Teaching", "description": "Teaching.", "findings": [ { "id": "teaching-finding", "name": "Teaching", "description": "Teaching.", "questions": [ { "text": "How are reaction types taught, and how are equations balanced?", "kind": "action" }, { "text": "Which entry fits chemical equation?", "kind": "action" } ] } ] }, { "id": "history", "name": "History", "description": "History.", "findings": [ { "id": "history-finding", "name": "History", "description": "History.", "questions": [ { "text": "How were displacement reactions and metathesis understood historically?", "kind": "provenance" }, { "text": "Which entry fits the history of chemistry?", "kind": "action" } ] } ] } ] } ] }, "openQuestions": [ "Should precipitation reaction and olefin metathesis be separate primary entries?", "How should chemistry references be linked?", "The registry entry has merged aliases naming a demonstration and a distinct organic reaction; should they be split off?" ], "statistics": { "bundles": 4, "layers": 8, "findings": 8, "questions": 16 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "abstract concept", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a double displacement reaction, record what state it is in, and decide what may be done with it.", "whatItIs": "Let an agent explain double displacement reactions and their pattern, relay salt metathesis, driving forces and demonstrations from chemistry references, describe olefin metathesis as a related but distinct reaction, and distinguish double displacement from single displacement, acid-base and redox reactions.", "characteristics": { "substance": "activity", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "observed and measured" ], "distinguishingFeatures": [ "Names folded into this entry, which a task may need to split apart again: golden rain demonstration, Salt metathesis reaction, olefin metathesis.", "3 finer distinctions are held as aliases rather than separate entries, because telling them apart needs a task that asks for it.", "Described in 38 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a double displacement reaction, and on what evidence are they told apart?" ], "whatItIsMadeOf": "something that happens over time", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "observe it, measure it, record its state" ], "howItIsRecognised": [ "Nothing to see. What is recognised is an instance of it, and which instances count is exactly what is argued about." ], "relatedModels": [ { "relation": "covers", "note": "Finer kinds folded into this entry because telling them apart needs a task that asks for it. Each is a model waiting to be split out when one does.", "targets": [ "golden rain demonstration", "Salt metathesis reaction", "olefin metathesis" ] } ], "standing": "Described in 38 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is. 3 finer distinctions are held inside this entry as names rather than as separate models.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one double displacement reaction from another, and a double displacement reaction from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a double displacement reaction sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a double displacement reaction from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a double displacement reaction passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a double displacement reaction between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a double displacement reaction, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a double displacement reaction is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "process-and-outcome", "name": "Process, inputs and outcome", "description": "How a double displacement reaction proceeds, what it needs and what it leaves behind.", "rationale": "An activity is known by its steps and its results, and both have to be recordable while it is still running.", "layers": [ { "id": "steps-and-sequence", "name": "Steps and sequence", "description": "The steps of a double displacement reaction, their order and what may run in parallel.", "findings": [ { "id": "steps-and-preconditions", "name": "Steps, preconditions and completion", "description": "What has to be true before each step of a double displacement reaction and what marks it done.", "questions": [ { "id": "steps-and-preconditions-q01", "text": "What identifies and describes a step of a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "steps-and-preconditions-q02", "text": "Who or what asserted this about a step of a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "steps-and-preconditions-q03", "text": "What may an agent decide or do once a step of a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "inputs-and-results", "name": "Inputs, resources and results", "description": "What a double displacement reaction consumes and what it produces.", "findings": [ { "id": "inputs-and-outputs", "name": "Inputs, outputs and side effects", "description": "The resources a double displacement reaction takes and the results it leaves, wanted or not.", "questions": [ { "id": "inputs-and-outputs-q01", "text": "What identifies and describes the inputs and results of a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "inputs-and-outputs-q02", "text": "Who or what asserted this about the inputs and results of a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "inputs-and-outputs-q03", "text": "What may an agent decide or do once the inputs and results of a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "definitions-in-contest", "name": "Definitions and who holds them", "description": "What double displacement reaction is taken to mean, and by whom.", "rationale": "When a field disagrees about a concept, the disagreement is the content. A model that picks one definition silently destroys the information.", "layers": [ { "id": "competing-definitions", "name": "Competing definitions", "description": "The main readings and the traditions behind them.", "findings": [ { "id": "definition-map", "name": "Definitions and their holders", "description": "Each definition with the school or body that holds it.", "questions": [ { "id": "definition-map-q01", "text": "Which definitions of double displacement reaction are in use, and which tradition or body holds each?", "kind": "definition" }, { "id": "definition-map-q02", "text": "What turns on the difference between them in practice?", "kind": "boundary" } ] } ] }, { "id": "operationalisation", "name": "Operationalisation", "description": "How it is measured or applied when it has to be.", "findings": [ { "id": "operational-record", "name": "Measures and proxies", "description": "Instruments and indicators used to stand in for it.", "questions": [ { "id": "operational-record-q01", "text": "How is double displacement reaction operationalised or measured in practice, and by what instrument?", "kind": "measurement" }, { "id": "operational-record-q02", "text": "What does that operationalisation leave out, and when does that matter?", "kind": "boundary" } ] } ] } ] }, { "id": "instances-and-use", "name": "Instances, use and consequence", "description": "What counts as an instance of double displacement reaction and what follows from calling something that.", "rationale": "Applying a concept is an act with consequences, so a model must say what the label licenses and what it does not.", "layers": [ { "id": "instances", "name": "What counts as an instance", "description": "Clear cases, borderline cases and non-cases.", "findings": [ { "id": "instance-tests", "name": "Tests for an instance", "description": "What would settle whether something falls under it.", "questions": [ { "id": "instance-tests-q01", "text": "What would settle whether something is an instance of double displacement reaction?", "kind": "boundary" }, { "id": "instance-tests-q02", "text": "Which borderline cases are argued about, and on what grounds?", "kind": "definition" } ] } ] }, { "id": "consequence", "name": "Consequence of application", "description": "Rights, duties or decisions that follow from the label.", "findings": [ { "id": "consequence-record", "name": "What the label licenses", "description": "What an agent may do once something is classified this way.", "questions": [ { "id": "consequence-record-q01", "text": "What follows practically once something is treated as double displacement reaction?", "kind": "action" }, { "id": "consequence-record-q02", "text": "What must an agent not infer from the label alone?", "kind": "action" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a double displacement reaction came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a double displacement reaction and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a double displacement reaction is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a double displacement reaction, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a double displacement reaction, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a double displacement reaction is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 6, "layers": 12, "findings": 14, "questions": 38 } } } }