{
  "vercy": "1.0-draft",
  "publication": {
    "status": "research-draft",
    "adjudicationStatus": "unreviewed",
    "publishableCanonical": false,
    "generatedAt": "2026-09-13T03:39:09Z",
    "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": 3,
    "engine": "claude",
    "enrichment": {
      "pass": 3,
      "engine": "claude",
      "producedAt": "2026-10-06T10:00:00Z",
      "ingestedAt": "2026-10-06T07:05:55+00:00",
      "fields": [
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        "ethics",
        "owners"
      ]
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    "revisions": [
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        "engine": "codex",
        "fields": [
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          "definition",
          "distinguishing_features",
          "visual_identification"
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    "gate": {
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      "evidence": [
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        "2 live sources",
        "review by codex: pass"
      ]
    }
  },
  "metaModel": {
    "id": "THING-Q1131951",
    "registryId": "vr.tr.acidity-function",
    "name": "acidity function",
    "version": "0.2.0-wave.3",
    "entryKind": "thing",
    "family": "Thing Registry",
    "domain": [
      "XCT.QTY"
    ],
    "status": "research-draft"
  },
  "canonicalUrl": "https://ver.cy/models/thing/q1131951/",
  "model": {
    "registry_id": "vr.tr.acidity-function",
    "name": "acidity function",
    "purpose": "Let an agent explain acidity functions and the Hammett function, relay definitions, values and uses from physical chemistry references, describe superacids, and distinguish acidity functions from pH and pKa.",
    "definition": "An indicator-dependent measure of the acidity of a solvent system, used particularly for concentrated acids, non-aqueous solvents and superacids where ordinary dilute-aqueous pH conventions may not adequately describe protonating ability. Appropriate pH definitions and scales can exist for such media, but acidity functions are distinct measures rather than a universal extension of pH. The best known is the Hammett acidity function H0, defined from the protonation of weak indicator bases and taking large negative values for superacids such as fluorosulfuric acid and magic acid, with related functions for other base types and for basic media. Acidity functions are used in physical organic chemistry to compare media and study acid-catalysed reactions.",
    "what_it_is_for": "Quantifying acidity beyond the pH range.",
    "affordances": [
      "explain the definition",
      "relay values and uses",
      "describe superacids",
      "distinguish from pH and pKa"
    ],
    "distinguishing_features": [
      "Acidity functions have indicator-based definitions.",
      "They characterise medium acidity through indicator equilibria rather than a universal extension of pH.",
      "They can describe acidity in the superacid range.",
      "Their values depend on the medium."
    ],
    "appearance": "Not a visible object; a numerical scale.",
    "visual_identification": [
      "Acidity functions measure solvent-system acidity, particularly in concentrated and non-aqueous media.",
      "Examples include Hammett H0, HR, H_ and other acidity functions.",
      "pH describes hydrogen ion activity under an applicable definition and scale, while pKa characterises a specific acid dissociation equilibrium in a specified medium."
    ],
    "physical_properties": [
      {
        "quantity": "H0 of 100 percent sulfuric acid",
        "typical_range": "about -12",
        "unit": "value",
        "note": ""
      },
      {
        "quantity": "H0 of magic acid",
        "typical_range": "about -23",
        "unit": "value",
        "note": ""
      },
      {
        "quantity": "introduced",
        "typical_range": "1932",
        "unit": "year",
        "note": "Hammett and Deyrup"
      }
    ],
    "families_and_kinds": [
      "Hammett acidity function H0",
      "HR and other functions for different indicator types",
      "H_ functions for basic media",
      "acidity functions in non-aqueous solvents",
      "gas-phase acidity as a related measure"
    ],
    "related_models": [
      {
        "relation": "is a kind of",
        "target": "metric",
        "why": "in registry terms"
      },
      {
        "relation": "extends",
        "target": "pH",
        "why": "to concentrated acids"
      },
      {
        "relation": "characterises",
        "target": "superacid",
        "why": "media"
      },
      {
        "relation": "was introduced by",
        "target": "Louis Plack Hammett",
        "why": "in 1932"
      }
    ],
    "identifiers": [],
    "standards_and_regulation": [
      "IUPAC definitions of acidity functions",
      "No regulation"
    ],
    "failure_modes_and_hazards": [
      "Applying pH concepts to superacids",
      "Comparing functions across different indicator types",
      "Superacid handling hazards"
    ],
    "in_scope": [],
    "out_of_scope": [],
    "characteristics": [],
    "agent_conduct": {
      "may": [
        "Explain what acidity functions measure and why ordinary dilute-aqueous pH conventions may be inadequate for concentrated acids and superacids, while appropriate pH definitions and scales can exist.",
        "Compare published values, stating the indicator family each function is based on.",
        "Point to safety data and the need for trained supervision when discussing superacids."
      ],
      "must_not": [
        "Give instructions for preparing, handling or using superacids or concentrated acids.",
        "Compare values from different acidity functions as if they were on one scale.",
        "Apply ordinary pH rules to superacid media.",
        "Invent numerical values for an acidity function."
      ],
      "requires_human": [
        "Any laboratory work with superacids or highly concentrated acids requires human oversight."
      ]
    },
    "ethics": {
      "considerations": [
        "Superacids and concentrated acids cause severe burns and toxic exposure.",
        "Accurate data matters for research and industrial safety."
      ],
      "affected_parties": [
        "Chemists and students",
        "Laboratory staff",
        "People near laboratories"
      ]
    },
    "owners": {
      "steward": "Nobody owns the measure; the scientific community maintains it.",
      "master_systems": []
    }
  },
  "sources": [
    {
      "id": "wikidata",
      "title": "Wikidata item Q1131951: acidity function",
      "url": "https://www.wikidata.org/wiki/Q1131951",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    },
    {
      "id": "wikipedia-en",
      "title": "Wikipedia: Acidity function",
      "url": "https://en.wikipedia.org/wiki/Acidity_function",
      "url_status": "live",
      "what_it_supports": "general description of the item",
      "checked_by": "wikidata-api sitelink"
    }
  ],
  "structure": {
    "bundles": [
      {
        "id": "understand",
        "name": "Understand",
        "description": "What an acidity function is.",
        "rationale": "Science.",
        "layers": [
          {
            "id": "definition",
            "name": "Definition",
            "description": "Definition.",
            "findings": [
              {
                "id": "definition-finding",
                "name": "Definition",
                "description": "Definition.",
                "questions": [
                  {
                    "text": "What is an acidity function, and how is the Hammett H0 defined from indicator protonation?",
                    "kind": "definition"
                  },
                  {
                    "text": "Is the question about acidity functions, pH or pKa?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          },
          {
            "id": "kinds",
            "name": "Kinds",
            "description": "Kinds.",
            "findings": [
              {
                "id": "kinds-finding",
                "name": "Kinds",
                "description": "Kinds.",
                "questions": [
                  {
                    "text": "What other acidity functions exist, and why do different indicator types give different scales?",
                    "kind": "definition"
                  },
                  {
                    "text": "Which entry fits the specific function?",
                    "kind": "action"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "measure",
        "name": "Measure",
        "description": "Measurement and values.",
        "rationale": "Science.",
        "layers": [
          {
            "id": "measurement",
            "name": "Measurement",
            "description": "Measurement.",
            "findings": [
              {
                "id": "measurement-finding",
                "name": "Measurement",
                "description": "Measurement.",
                "questions": [
                  {
                    "text": "How are acidity functions measured with overlapping indicators and spectroscopy?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which references are standard?",
                    "kind": "provenance"
                  }
                ]
              }
            ]
          },
          {
            "id": "values",
            "name": "Values",
            "description": "Values.",
            "findings": [
              {
                "id": "values-finding",
                "name": "Values",
                "description": "Values.",
                "questions": [
                  {
                    "text": "What H0 values do sulfuric acid, fluorosulfuric acid and magic acid have?",
                    "kind": "measurement"
                  },
                  {
                    "text": "Which sources are cited?",
                    "kind": "provenance"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "apply",
        "name": "Apply",
        "description": "Applications.",
        "rationale": "Application.",
        "layers": [
          {
            "id": "kinetics",
            "name": "Kinetics",
            "description": "Reaction kinetics.",
            "findings": [
              {
                "id": "kinetics-finding",
                "name": "Kinetics",
                "description": "Kinetics.",
                "questions": [
                  {
                    "text": "How are acidity functions used to study acid-catalysed reaction mechanisms?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits acid catalysis?",
                    "kind": "action"
                  }
                ]
              }
            ]
          },
          {
            "id": "superacids",
            "name": "Superacids",
            "description": "Superacids.",
            "findings": [
              {
                "id": "superacids-finding",
                "name": "Superacids",
                "description": "Superacids.",
                "questions": [
                  {
                    "text": "What are superacids, and how are they used in chemistry and industry, in general terms?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits superacid?",
                    "kind": "action"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "context",
        "name": "Context",
        "description": "History and theory.",
        "rationale": "Context.",
        "layers": [
          {
            "id": "history",
            "name": "History",
            "description": "History.",
            "findings": [
              {
                "id": "history-finding",
                "name": "History",
                "description": "History.",
                "questions": [
                  {
                    "text": "How did Hammett develop the acidity function, and how did Olah extend superacid chemistry?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits the history of physical organic chemistry?",
                    "kind": "action"
                  }
                ]
              }
            ]
          },
          {
            "id": "theory",
            "name": "Theory",
            "description": "Theory.",
            "findings": [
              {
                "id": "theory-finding",
                "name": "Theory",
                "description": "Theory.",
                "questions": [
                  {
                    "text": "What are the theoretical assumptions and limits of acidity functions?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits acid-base theory?",
                    "kind": "action"
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  },
  "openQuestions": [
    "Should Hammett acidity function and superacid be separate primary entries?",
    "How should physical chemistry references be linked?",
    "How should measured values be sourced?"
  ],
  "statistics": {
    "bundles": 4,
    "layers": 8,
    "findings": 8,
    "questions": 16
  }
}