{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.dihydroxybenzoic-acid","code":"thing-q913364","url":"https://ver.cy/models/thing/q913364/","name":"dihydroxybenzoic acid","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.MAT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"Dihydroxybenzoic acid denotes any of six positional isomers of benzoic acid bearing two hydroxyl groups on the benzene ring, each with molecular formula C7H6O4.","purpose":"Enable an agent to identify dihydroxybenzoic acid at the correct isomer resolution, assess a material sample and determine whether its documented condition supports an intended use.","scope":{"in":["Benzoic acid structures bearing two additional hydroxyl groups on the aromatic ring","Positional-isomer identity and explicitly unresolved identity","Sample purity, isomer composition, water content and grade","Physical properties and solution behavior under recorded conditions","Evidence supporting handling, storage and application suitability"],"out":["Separate substance identities for salts, esters and other covalent derivatives","Finished formulations containing dihydroxybenzoic acid","Manufacturing processes and synthesis equipment","Organisms and metabolic pathways in which an isomer occurs","Complete analytical methods and instrument models","Therapeutic efficacy or authorization of products containing an isomer"],"boundaries":[]},"distinguishingFeatures":["Require one carboxylic acid group attached directly to a benzene ring and two additional ring hydroxyl groups; the hydroxyl within the carboxyl group does not count toward 'dihydroxy'.","Require hydroxyl locants to distinguish positional isomers: 2,3- and 2,4-dihydroxybenzoic acid are distinct structures despite sharing formula C7H6O4. Sources: [ChEBI 2,3-isomer](https://www.ebi.ac.uk/chebi/searchId.do?chebiId=18026), [ChEBI 2,4-isomer](https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI%3A42094).","Distinguish the neutral acid from a dihydroxybenzoate ion or isolated salt by charge, protonation and counterion evidence. Source: [ChEBI acid-conjugate-base relationship](https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI%3A42094).","Treat an unspecified isomer and a demonstrated mixture of isomers as different information states.","Reject identity based only on molecular formula, nominal mass or the abbreviation DHB; require structure-resolving evidence or a verified identifier."],"structure":{"bundles":[{"id":"isomer-identity","name":"Isomer identity","description":"Resolve what the unqualified registry name and a particular material actually denote.","layers":[{"id":"registry-meaning","name":"Registry meaning","description":"Preserve the registered concept while investigating its intended chemical granularity.","findings":[{"id":"unqualified-name-resolution","name":"Unqualified name resolution","description":"Record whether the source entry denotes a chemical family or an individual isomer; do not silently choose an isomer.","questions":[{"text":"Does the originating registry record specify hydroxyl locants, a structure or an isomer-specific identifier?","id":"unqualified-name-resolution-q01","kind":"provenance"},{"text":"Does an existing catalogue model already own this concept or the identified isomer?","id":"unqualified-name-resolution-q02","kind":"boundary"}]}]},{"id":"molecular-identity","name":"Molecular identity","description":"Establish ring substitution and the chemical form represented by identifiers.","findings":[{"id":"structure-identifier-agreement","name":"Structure and identifier agreement","description":"Require agreement among hydroxyl locants, molecular structure, charge and external identifiers.","questions":[{"text":"Which ring positions carry the two hydroxyl groups relative to the carboxyl-bearing carbon?","id":"structure-identifier-agreement-q01","kind":"definition"},{"text":"Do the CAS, PubChem, EC and structural records refer to the same positional isomer and acid form?","id":"structure-identifier-agreement-q02","kind":"provenance"},{"text":"Is the material the free acid, an isolated salt or a derivative requiring a linked substance identity?","id":"structure-identifier-agreement-q03","kind":"boundary"}]}]}]},{"id":"composition-and-verification","name":"Composition and verification","description":"Establish what fraction of a sample is the intended dihydroxybenzoic acid isomer.","layers":[{"id":"isomer-confirmation","name":"Isomer confirmation","description":"Connect sample identification to evidence capable of resolving substitution patterns.","findings":[{"id":"isomer-discriminating-evidence","name":"Isomer-discriminating evidence","description":"Distinguish evidence for elemental composition from evidence for hydroxyl positions.","questions":[{"text":"What NMR assignments, reference-standard comparison or other validated evidence establishes the hydroxyl positions?","id":"isomer-discriminating-evidence-q01","kind":"measurement"},{"text":"Does the analytical method distinguish the intended isomer from the plausible co-occurring isomers?","id":"isomer-discriminating-evidence-q02","kind":"measurement"}]}]},{"id":"usable-material-content","name":"Usable material content","description":"Account for assay basis, other isomers, water and residual solvents.","findings":[{"id":"assay-basis-and-impurities","name":"Assay basis and impurities","description":"Record quantities and methods without equating chromatographic area purity with mass purity.","questions":[{"text":"Is the reported assay for the intended isomer or total dihydroxybenzoic acids, and is it on an as-received or dry basis?","id":"assay-basis-and-impurities-q01","kind":"measurement"},{"text":"What other isomers, water, residual solvents or unidentified components are measured or unresolved?","id":"assay-basis-and-impurities-q02","kind":"measurement"},{"text":"Does the lot-specific certificate substantiate the purity and impurity limits needed for the proposed use?","id":"assay-basis-and-impurities-q03","kind":"action"}]}]}]},{"id":"physical-and-solution-state","name":"Physical and solution state","description":"Describe the identified isomer under the conditions of storage, measurement and preparation.","layers":[{"id":"solid-and-thermal-state","name":"Solid and thermal state","description":"Relate the material form to observed phase transitions and thermal limits.","findings":[{"id":"form-specific-thermal-evidence","name":"Form-specific thermal evidence","description":"Keep melting, solvent loss and decomposition observations distinct.","questions":[{"text":"What evidence identifies the sample's crystallinity and any hydrate or solvate form?","id":"form-specific-thermal-evidence-q01","kind":"measurement"},{"text":"Which measured thermal events are melting, solvent loss or decomposition, and under what heating conditions?","id":"form-specific-thermal-evidence-q02","kind":"measurement"}]}]},{"id":"dissolution-and-speciation","name":"Dissolution and speciation","description":"Connect solvent and pH conditions to dissolved concentration and protonation.","findings":[{"id":"conditioned-solubility","name":"Conditioned solubility","description":"Record solubility and acid dissociation evidence for the specified positional isomer.","questions":[{"text":"What concentration dissolves at the intended solvent composition, temperature and pH?","id":"conditioned-solubility-q01","kind":"measurement"},{"text":"Which dissociation steps do reported pKa values describe, and under what measurement conditions?","id":"conditioned-solubility-q02","kind":"measurement"},{"text":"Does the intended preparation retain the required dissolved concentration after pH adjustment or cooling?","id":"conditioned-solubility-q03","kind":"action"}]}]}]},{"id":"stability-and-handling","name":"Stability and handling","description":"Determine whether a sample remains chemically suitable and how it may be handled.","layers":[{"id":"chemical-integrity","name":"Chemical integrity","description":"Investigate change during storage and use without presuming a universal degradation pathway.","findings":[{"id":"condition-dependent-change","name":"Condition-dependent change","description":"Track evidence of oxidation, other degradation or composition changes under relevant conditions.","questions":[{"text":"What evidence establishes stability under the proposed light, oxygen, temperature and solution-pH conditions?","id":"condition-dependent-change-q01","kind":"provenance"},{"text":"Do changes in color, assay or chromatographic profile indicate a need for reanalysis?","id":"condition-dependent-change-q02","kind":"action"}]}]},{"id":"applicable-handling-evidence","name":"Applicable handling evidence","description":"Connect handling requirements to identity-matched safety documentation.","findings":[{"id":"isomer-specific-safety-basis","name":"Isomer-specific safety basis","description":"Record documented hazards and distinguish missing exposure information from evidence of no hazard.","questions":[{"text":"Which current SDS and classification records match the positional isomer, supplied form and jurisdiction?","id":"isomer-specific-safety-basis-q01","kind":"provenance"},{"text":"Are substance-specific exposure limits documented, or does the available record leave them unresolved?","id":"isomer-specific-safety-basis-q02","kind":"provenance"},{"text":"What controls and storage conditions do those records require for the proposed quantity and operation?","id":"isomer-specific-safety-basis-q03","kind":"action"}]}]}]},{"id":"application-fitness","name":"Application fitness","description":"Determine whether the exact isomer and lot support a named analytical or chemical task.","layers":[{"id":"use-evidence","name":"Use evidence","description":"Bind a proposed function to the isomer and conditions for which it is demonstrated.","findings":[{"id":"isomer-bound-function","name":"Isomer-bound function","description":"Assess proposed roles such as analytical standard, matrix or reaction reagent through matching evidence.","questions":[{"text":"Which positional isomer does the intended method or application explicitly require?","id":"isomer-bound-function-q01","kind":"definition"},{"text":"What evidence demonstrates the required function under the proposed conditions?","id":"isomer-bound-function-q02","kind":"provenance"},{"text":"Would changing the isomer or grade require separate qualification?","id":"isomer-bound-function-q03","kind":"boundary"}]}]},{"id":"lot-release-decision","name":"Lot release decision","description":"Translate identity, assay and condition evidence into an operational decision.","findings":[{"id":"preparation-and-acceptance","name":"Preparation and acceptance","description":"Use documented acceptance criteria and composition corrections to qualify a sample for a specific task.","questions":[{"text":"What identity, assay, impurity and stability criteria must this lot meet before use?","id":"preparation-and-acceptance-q01","kind":"action"},{"text":"What weighed quantity is required after accounting for the applicable assay and water-content basis?","id":"preparation-and-acceptance-q02","kind":"measurement"},{"text":"Which unresolved results require quarantine, additional analysis or rejection for this task?","id":"preparation-and-acceptance-q03","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-identifiers","name":"Identifiers and schemes","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these identifiers and schemes hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-identifiers-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of dihydroxybenzoic acid this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Describe the six isomers and their roles in chemistry and biology from scientific sources.","Track samples, labels and safety data sheets in a laboratory inventory it manages."],"mustNot":["Mislabel one isomer as another in records or on containers.","Recommend these compounds as supplements or treatments to people.","Dispose of them into drains or the environment against rules."],"requiresHuman":["Approving a new use in food, cosmetics or medicine."]},"ethics":{"considerations":["Isomers differ in effects, so mix-ups can harm research and patients.","Workers handling fine chemical powders need protection."],"affectedParties":["Laboratory workers","Patients in studies","Researchers"]},"owners":{"steward":"Nobody owns the compounds; the holder of a sample answers for it.","roles":[],"masterSystems":[]},"relations":[{"target":"Q105193245","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.dihydroxybenzoic-acid","Wikidata: Q913364 (https://www.wikidata.org/wiki/Q913364)"]},"properties":{"applicability":"required","items":["Identity resolution: family only | specified positional isomer | characterized isomer mixture | conflicting identity","Hydroxyl substitution positions: Ring locants relative to the carboxyl-bearing carbon at position 1; unresolved allowed","Verified chemical identifiers: Structure-linked CAS, PubChem CID, ChEBI, EC, InChI or SMILES records, with source and identity scope","Assay and isomer composition: Mass %, mol % or method-specific chromatographic area %, with reporting basis","Water and residual solvent: Mass % or mg/kg, with method and sampling date","Physical form: Solid or dissolved; crystallinity, hydrate or solvate status where established; temperature and pressure","Thermal behavior: Melting interval and decomposition onset in °C; boiling data only with pressure and evidence","Solubility: g/L or mol/L with solvent, temperature, pH and equilibration method","Acid dissociation and solution speciation: Dimensionless pKa with dissociation assignment, solvent, temperature and ionic strength","Hazard and regulatory evidence: Applicable SDS, GHS classification and exposure-limit records by isomer, form, jurisdiction and revision date","Application qualification: Qualified | conditional | unassessed | rejected for a named use and acceptance criteria"]},"recognition":{"applicability":"required","items":["White to off-white crystalline powders; isomers cannot be told apart by eye."]},"capabilities":{"applicability":"required","items":["Resolve a label or identifier to a supported positional-isomer identity while preserving uncertainty.","Select confirmatory analyses that distinguish the intended isomer from plausible alternatives.","Calculate a preparation quantity using assay, water content and the specified chemical form.","Compare solubility and thermal evidence against proposed preparation conditions.","Accept, quarantine or reject a sample against documented application requirements.","Derive handling and storage requirements from evidence applicable to the identified material."]},"hazards":{"applicability":"required","items":["Dust irritates eyes, skin and airways.","Wrong isomer identification invalidates results."]},"interfaces":{"applicability":"required","items":["Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances (CLP), European Union."]},"context":{"applicability":"required","items":["Dihydroxybenzoic acids are encountered in studies of plant chemistry, microbial metabolism and chemical synthesis.","Individual isomers can serve as analytical reference materials or starting materials for preparing other compounds.","The hydroxyl group positions must be specified because the isomers differ in their properties and suitability for a particular use."]}},"sources":[{"title":"Wikidata item Q913364: dihydroxybenzoic acid","url":"https://www.wikidata.org/wiki/Q913364","note":"identity and sense of the item"},{"title":"Wikipedia: Dihydroxybenzoic acid","url":"https://en.wikipedia.org/wiki/Dihydroxybenzoic_acid","note":"general description of the item"}],"openQuestions":["Does the originating record intend the positional-isomer family or a particular isomer, and what evidence resolves that scope?","Does an existing Vercy model already cover this family or its intended member, requiring linkage rather than another publication?","Which authoritative identifier mappings and structure-discriminating analytical references should anchor each supported isomer?","Which isomer- and form-specific thermal, solubility, dissociation and stability measurements are reliable enough to support decisions?","Which current safety records and application acceptance criteria apply to the actual isomers, grades and jurisdictions encountered?"],"resources":{"spec":"/models/things/publications/thing-q913364/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q913364/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T09:11:17Z","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 2026-10-07T10:10:33+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}