zinc oxide
Enable an AI agent to identify zinc oxide material, assess its condition and suitability, and select justified handling, processing or use actions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to identify zinc oxide material, assess its condition and suitability, and select justified handling, processing or use actions.
Zinc oxide is the II-VI compound ZnO, an amphoteric, water-insoluble white solid that crystallizes predominantly in the hexagonal wurtzite structure, acts as a wide-band-gap semiconductor, and is manufactured mainly as a rubber-vulcanization activator, white pigment, pharmaceutical astringent, and inorganic UV filter.
It can be Identify and quantify zinc oxide using evidence appropriate to its form and surrounding material.; Compare zinc oxide grades using compatible assays, particle measurements and surface-treatment records.; Select material for a stated optical, electrical, formulation or processing role against explicit acceptance criteria.; Authorize dispersion, milling, coating or thermal treatment when applicable constraints and post-treatment checks are recorded.; Hold, segregate or retest zinc oxide after contamination, agglomeration or an undocumented processing excursion.; Route handling and release decisions to the applicable exposure, environmental and product requirements..
Distinguishing features
Require chemical identity consistent with ZnO; a zinc-containing label alone does not establish zinc oxide. Reference identity: [PubChem zinc oxide](https://pubchem.ncbi.nlm.nih.gov/compound/Zinc-Oxide).
Use phase-sensitive evidence, such as an appropriate diffraction or spectroscopic comparison, to distinguish zinc oxide from zinc metal, zinc peroxide, zinc hydroxide and zinc carbonate; total zinc measurement alone is insufficient.
For a white powder, require analytical identification rather than appearance to distinguish zinc oxide from titanium dioxide or other white fillers.
Establish whether the record represents zinc oxide itself, surface-treated zinc oxide, or a mixture containing a stated zinc oxide fraction.
Distinguish primary particles, crystallites and dispersed agglomerates before accepting a size-based grade or nano designation.
Scope
+ Evidence that a material or component is zinc oxide and the limits of that identification.
+ Batch-specific purity, secondary phases, dopants and surface treatments.
+ Powders, particles, crystals, films and dispersions, with their relevant size and morphology.
+ Changes in zinc oxide condition during storage, dispersion, illumination or thermal processing.
+ Application-specific material performance and evidence supporting permitted actions.
- Elemental zinc, zinc peroxide, zinc hydroxide and other zinc compounds as separate substances.
- Complete sunscreen, ointment, rubber, paint or ceramic formulations and their product performance.
- Finished semiconductor devices, sensors and their circuit behavior.
- Mining deposits and mineral specimens beyond their zinc oxide component.
- Patient treatment decisions and organism-level zinc nutrition.
- Facility-wide exposure management, wastewater treatment and disposal operations.
Characteristics
- Identity evidence
- confirmed | provisional | conflicting | untested; analytical method and reference Determines whether zinc oxide-specific decisions are justified.
- Zinc oxide content
- mass %; as-received or dry basis; method and uncertainty Separates zinc oxide content from total zinc and from the mass of coatings or carriers.
- Phase composition
- identified phases; phase fractions where quantified; detection limits Reveals secondary compounds or structural differences hidden by a bulk elemental assay.
- Impurity and dopant profile
- mg/kg, mass % or atomic % by constituent; intentional status recorded Supports grade selection and distinguishes deliberate modification from contamination.
- Material form
- powder | dispersion | crystal | film | other specified form Selects relevant characterization, processing and exposure questions.
- Particle size and morphology
- nm or µm; distribution basis, shape, method and primary-particle or agglomerate designation Prevents substitution based on incomparable size measurements.
- Specific surface area
- m²/g; method and sample pretreatment Provides a surface-related comparison for powders beyond nominal particle diameter.
- Surface treatment
- treatment substance, loading, coverage evidence and treatment history; untreated or unknown Connects the ZnO core to modifications relevant to dispersion and surface behavior.
- Dissolution and zinc release
- dissolved zinc in mg/L and fraction released over time; medium, pH, temperature and separation method Distinguishes retained particles from dissolved zinc under the intended conditions.
- Optical response
- spectral transmittance, reflectance or absorbance; wavelength in nm and specimen geometry Supports optical selection without treating a material spectrum as finished-product protection.
- Electrical response
- resistivity in Ω·m or application-specific response; temperature, illumination and specimen preparation Makes electrical suitability conditional on the actual material and test conditions.
- Lot qualification
- unassessed | qualified for stated use | restricted | rejected | awaiting retest Connects evidence to a specific decision without making suitability universal.
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
ZnO identity and composition Establishes what portion of the material is zinc oxide and what else accompanies it.
A zinc assay or commercial name cannot alone establish ZnO identity, phase purity or usable content.
Compound and phase identity
Separates identification of ZnO from identification of zinc or a visually similar powder.
Supported ZnO identification
Record the analytical evidence, reference comparison and unresolved alternatives behind the identity decision.
- What evidence identifies ZnO rather than zinc metal or another zinc compound? definition
- Which phases could remain undetected or unresolved by the methods used? boundary
Assay and associated constituents
Accounts for ZnO, secondary phases, impurities, dopants and non-ZnO mass.
Interpretable composition
Record composition on an explicit basis and separate directly measured ZnO from values inferred from total zinc.
- Is the reported assay ZnO content or total zinc converted to a ZnO equivalent, and on what mass basis? measurement
- Which impurities, dopants, coatings or carriers are present, and which were deliberately introduced? provenance
Particle and surface state Characterizes the physical presentation and accessible surface of the ZnO.
Chemically matching ZnO materials can require different decisions because particle assembly and surface treatment differ.
Size and material form
Distinguishes particle, agglomerate, crystallite and continuous-material measurements.
Form-appropriate dimensions
Record dimensions using methods and descriptors appropriate to powder, dispersion, crystal or film.
- Is this ZnO a powder, dispersion, crystal or film, and which dimensions control its intended use? definition
- Does each reported size describe primary particles, crystallites, agglomerates or film thickness, and how was it measured? measurement
Surface treatment and dispersion
Records the ZnO surface and its condition in a specified carrier.
Surface and dispersion evidence
Connect surface-treatment identity and accessible area to observed wetting, settling or agglomeration.
- What coating or treatment is present, and what evidence establishes its loading and coverage? provenance
- In the intended carrier, what measurements establish dispersion stability and changes in agglomerate size? measurement
Chemical and processing state Tracks whether storage or processing has changed the ZnO being evaluated.
An initial ZnO certificate does not establish the identity and condition of material after subsequent treatment.
Medium-dependent transformation
Distinguishes particulate ZnO from dissolved zinc and newly formed compounds.
Retained ZnO and released zinc
Record the chemical state reached in the actual contacting medium over the relevant duration.
- At the intended pH, temperature and contact time, how much zinc is dissolved and how much ZnO remains? measurement
- At what measured conversion does the resulting material require a linked model for a different compound or mixture? boundary
Storage and treatment history
Links condition changes to humidity, atmosphere, light, heating and mechanical treatment.
Post-treatment condition
Record relevant exposures and determine whether earlier identity, surface and size evidence still applies.
- What storage conditions, illumination, milling or thermal treatments occurred after the last characterization? provenance
- Which phase, surface or particle measurements must be repeated before this ZnO can be released for use? action
Use-specific performance Connects measured ZnO behavior to a defined material role.
A grade suitable for one ZnO application cannot be assumed suitable for another.
Optical and electrical behavior
Records relevant spectra or electrical measurements under reproducible conditions.
Conditioned functional response
Keep specimen geometry, preparation and environment attached to functional measurements.
- Which optical spectrum or electrical response is required for the intended role, and under what test conditions? measurement
- What evidence permits transferring the measured response to the intended loading, thickness or device environment? boundary
Formulation and process fit
Evaluates ZnO as an input to a specified formulation or transformation.
Qualified material role
Record the intended function and the trial evidence required before accepting or substituting a grade.
- Is this ZnO intended as a pigment, UV-attenuating ingredient, rubber activator, ceramic input or another specified material role? definition
- Which formulation or process trial must pass before this batch or substitute grade is accepted? action
ZnO action constraints Connects the specific ZnO form and intended operation to handling and qualification evidence.
Decisions must account for the actual exposure form and approved material use rather than relying on the substance name alone.
Operation and release pathways
Records potential airborne, liquid and waste pathways created by the proposed operation.
Form-specific handling decision
Identify the relevant exposure form and the evidence needed to select controls for that operation.
- Could the operation generate ZnO dust, aerosol or fume, or release particulate or dissolved zinc to liquid streams? boundary
- Which current safety document and operation-specific assessment support the selected containment and handling measures? action
Grade and lot release
Links a traceable ZnO lot to the requirements of its intended destination.
Evidence-backed release
Record applicable grade requirements, matching lot evidence and unresolved conditions that prevent release.
- Which supplier lot, certificate and analytical samples support this material's claimed ZnO grade? provenance
- For the intended use and jurisdiction, which missing or failed requirements require holding, retesting or rejecting the lot? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- French-process (indirect) ZnO from burned zinc-metal vapour
- American-process (direct) ZnO from oxidised ores or residues
- Wet-chemical / precipitated ZnO from zinc salts
- Nano-grade UV-filter ZnO, often silica- or silane-coated
- Pharmacopoeial (USP / Ph. Eur.) medicinal ZnO
- Active high-surface-area rubber grade
- Feed and veterinary ZnO, including high-dose weaner-pig grades
- Electronic-grade wurtzite ZnO (single crystals, epitaxial films, varistors)
- Which of these kinds and varieties hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- CAS Registry Number - 1314-13-2 - Principal registry number for ZnO.
- EC / EINECS - 215-222-5 - European inventory number used in REACH/CLP.
- PubChem CID - 14806 - NCBI compound record.
- Wikidata - Q190077 - Item for zinc oxide; confirm against the live item before treating as canonical.
- FDA UNII - SOI2LOH54Z - Substance identifier used in US drug and cosmetic listings.
- Colour Index - Pigment White 4 / CI 77947 - Pigment and cosmetic colour designation.
- INCI - Zinc Oxide - Cosmetic ingredient name; nano grades are labelled Zinc Oxide (nano) in the EU.
- InChIKey - XLOMVQKBTHCTTD-UHFFFAOYSA-N - Standard key for ZnO.
- HS / Harmonized System - 2817.00 - Heading covering zinc oxide and zinc peroxide; national splits then separate the two.
- Which of these identifiers and schemes hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- ASTM International: ASTM D79/D79M, zinc oxide pigments.
- ISO: ISO 9298, test methods for zinc oxide as a rubber compounding ingredient.
- United States Pharmacopeia: Zinc Oxide monograph.
- EDQM / European Pharmacopoeia: Zinc oxide monograph.
- US FDA: 21 CFR 73.1991 (drug colour additive); 21 CFR 182.8991 (GRAS nutrient); zinc oxide listed as a GRASE sunscreen active under the OTC sunscreen framework.
- European Commission: Regulation (EC) No 1223/2009 Annex VI, zinc oxide (including nano form) as a UV filter, with concentration and spray-application limits.
- ECHA / CLP: zinc oxide classified Aquatic Acute 1 and Aquatic Chronic 1 (H400/H410).
- European Commission / EMA CVMP: 2017 implementing decision withdrawing oral veterinary ZnO products for food-producing animals, with use ending in the EU in 2022.
- US OSHA / NIOSH: occupational limits for zinc oxide dust and fume (commonly 5 mg/m³ as fume), metal fume fever being the characteristic acute effect.
- Which of these standards and regulation hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Largest historical tonnage is as an activator and cure-control additive in sulphur-vulcanised rubber (tyres, hoses, footwear).
- White pigment and opacifier in paints, coatings, ceramics, glass, and paper, sold as zinc white.
- Broad-spectrum inorganic UV filter in sunscreens and daily cosmetics, including coated nanoparticles that look less white on skin.
- Topical medicine: calamine and zinc oxide ointments, diaper-rash pastes, and zinc oxide adhesive tape.
- Weaner-pig diets at pharmacological zinc levels to limit post-weaning diarrhoea (still used in several producing regions; no longer authorised as a VMP in the EU).
- Electroceramics: ZnO varistors, ferrite-related mixes, piezoelectric and SAW devices, transparent conductors, and gas sensors.
- Chemical intermediate and desulphurising / fluxing agent in some metallurgical and cement operations.
- Which of these real-world use hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Molar mass - 81.38 - g/mol
- Crystallographic density (wurtzite) - 5.6-5.61 - g/cm³
- Optical band gap (wurtzite, ~300 K) - 3.3-3.4 - eV
- Melting / sublimation temperature - about 1975 - °C
- BET specific surface area - standard French-process ~4-10; active rubber grades ~30-70 - m²/g
- Primary particle size - pigment 0.1-1; nano UV-filter typically 10-200 - µm for pigment, nm for nano grades
- Refractive index (wurtzite) - n ≈ 2.00-2.02 - dimensionless
- Assay as ZnO - industrial ≥99; pharmacopoeial typically ≥99.0 with Pb/Cd/As limits - mass %
- Which of these typical measurements hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Inhalation of freshly formed ZnO fume (welding or cutting galvanised steel) causes metal fume fever.
- Uncoated nano-ZnO is photocatalytic and can generate reactive oxygen species, degrading organic binders, sunscreen organics, and, in poorly formulated products, increasing phototoxic stress.
- Classified as very toxic to aquatic life; industrial and high-dose agricultural releases enrich soils and manure with zinc.
- Chronic excess zinc intake induces copper deficiency; large acute ingestion causes gastrointestinal zinc toxicity.
- Photocatalytic chalking of ZnO-pigmented paints and coatings if the binder is not stabilised.
- Poor dispersion of rubber-grade ZnO gives uneven cure, scorch, and physical-property scatter.
- Fine and nano dusts are an occupational inhalation concern even when acute toxicity is modest.
- High-dose veterinary use selects for zinc-tolerant bacteria and is implicated in co-selection of antimicrobial resistance.
- Which of these failure modes and hazards hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Trade still names product by process: French (indirect), American (direct), and various wet-process Asian grades.
- Pharmacological ZnO in weaner pigs was withdrawn in the EU in 2022; high-dose feed use remains common in the United States, China, Brazil, and other pig-producing regions.
- EU cosmetics law requires [nano] labelling and Annex VI conditions for nano-ZnO; the United States treats zinc oxide as a GRASE sunscreen active without an equivalent nano annex.
- Artists' materials use the names zinc white and Chinese white; rubber trade historically used White/Green/Red Seal grades tied to lead content.
- Japan, Korea, and parts of Europe concentrate electronic-grade crystals, varistors, and thin films, while bulk pigment and rubber grades are global commodity chemicals.
- Which of these regional variation hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Titanium dioxide (TiO2) - Also a white pigment and sunscreen UV filter; separate by XRF/ICP (Ti vs Zn) and XRD (rutile/anatase vs wurtzite). Rutile has a markedly higher refractive index (~2.7 vs ~2.0).
- Zinc peroxide (ZnO2) - Same HS heading family but different compound (CAS 1314-22-3); peroxide oxygen assay and thermal oxygen release distinguish it from ZnO.
- Lithopone (ZnS + BaSO4) - White zinc-containing pigment; barium assay, sulphide tests, and XRD show sphalerite/barite rather than wurtzite ZnO.
- Zinc sulphide (ZnS) - Acid plus evolution of H2S, and XRD of sphalerite/wurtzite-ZnS, versus acid dissolution of ZnO to Zn²⁺ with no sulphide.
- Magnesium oxide (MgO) - Similar white refractory oxide; density (~3.58 vs 5.61 g/cm³) and Mg vs Zn assay separate them.
- Calamine / zinc carbonate - Historical skin preparations mix ZnO with iron oxides or use basic zinc carbonate; carbonate gives CO2 on acid, and Fe₂O₃ tints the pink calamine grade.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of zinc oxide this model covers, and on what evidence? provenance
Sources
- PubChem Compound Summary for CID 14806, Zinc oxide - Formula, CAS, identifiers, physical constants, and regulatory flags used in the definition and identifier list.
- ASTM D79/D79M Standard Specification for Zinc Oxide Pigments - Pigment-grade specification practice and the distinction of zinc oxide as a named industrial pigment.
- ISO 9298 Rubber compounding ingredients - Zinc oxide - Test methods - Rubber-grade identity, test methods, and the industrial distinction of ZnO as a vulcanization activator.
- USP-NF monograph: Zinc Oxide - Pharmacopoeial identity, impurity limits, and medicinal-grade practice.
- 21 CFR 73.1991 Zinc oxide - US drug colour-additive listing for zinc oxide.
- ECHA substance information: zinc oxide (EC 215-222-5) - REACH/CLP classification, including aquatic acute and chronic toxicity, and European chemical identity.
- CVMP opinion and Commission Implementing Decision of 26 June 2017 on veterinary medicinal products containing zinc oxide for oral use in food-producing animals - EU withdrawal of pharmacological ZnO in piglets and the regional split in feed/veterinary use.
- NIOSH Pocket Guide to Chemical Hazards: Zinc oxide - Occupational exposure limits and metal-fume-fever hazard of zinc oxide fume.
What the second pass must settle
- Does an existing Vercy world model already own zinc oxide, requiring this registry entry to link to it?
- Which identity and assay methods reliably distinguish ZnO from relevant secondary zinc compounds in each supported material form?
- Which application-specific specifications should govern impurities, surface treatments and lot acceptance?
- Which particle-size definitions and measurement protocols should govern nano designations and comparisons between grades?
- What evidence is sufficient to predict dissolution, surface change and functional performance after realistic storage or processing?