ammonia
Enable an AI agent to recognise ammonia-bearing material, judge its current condition and determine which handling or use decisions require further evidence.
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 recognise ammonia-bearing material, judge its current condition and determine which handling or use decisions require further evidence.
Ammonia is the inorganic hydride NH3: a colourless, pungent, alkaline gas at ambient conditions that is readily liquefied under modest pressure, highly soluble in water as a weak Brønsted base in equilibrium with ammonium, and the principal reduced-nitrogen industrial intermediate from catalytic hydrogenation of dinitrogen.
It can be Request substance-specific identification or resolve an ambiguous ammonia label.; Compare composition and impurity evidence with a named application specification.; Assess whether observed temperature, pressure and phase are mutually consistent.; Evaluate a proposed storage, transfer, dilution or use operation against ammonia-specific constraints and linked procedures.; Flag release evidence or incompatible contact conditions for the appropriate operational response.; Hold, qualify or reject a material quantity when identity, condition or supporting evidence is insufficient..
Distinguishing features
Require identity evidence for NH3; an ammonium result alone does not establish that the material is ammonia.
Distinguish anhydrous ammonia from aqueous ammonia using measured or specified water content rather than the product name alone.
Distinguish free ammonia from total ammonia in solution by checking the analytical definition, reporting basis and sample conditions.
Distinguish refrigerated or pressurised liquid ammonia from aqueous ammonia: a liquid appearance does not establish that water is present.
Distinguish ammonia from amines or other alkaline materials through substance-specific identification; odour and pH alone are insufficient.
Scope
+ Identification of ammonia as NH3 and distinction from ammonium ions and ammonium salts
+ Anhydrous ammonia and ammonia in aqueous solution, with explicit composition boundaries
+ Physical phase and condition at recorded temperature and pressure
+ Purity, contaminants and suitability for a declared application
+ Ammonia-specific release, exposure and chemical compatibility constraints
+ Evidence needed to permit, restrict or defer an operation involving the material
- Design, inspection and maintenance of tanks, cylinders, valves and refrigeration equipment
- Design and operation of ammonia synthesis or conversion plants
- Independent models of ammonium salts and finished fertiliser formulations
- Clinical assessment and treatment of exposed people
- Facility-wide emergency response and environmental dispersion modelling
- Commercial contracts, shipment administration and lifecycle emissions accounting
Characteristics
- Material identity
- NH3 identity supported; ammonia-containing mixture; identity unresolved Prevents decisions based on a name, odour or nonspecific analytical result.
- Material form
- Anhydrous ammonia; aqueous ammonia; other ammonia-containing mixture; unresolved Separates materials whose concentration, phase behaviour and handling requirements differ.
- Ammonia concentration
- Mass fraction, molar concentration or gas mole fraction, with explicit NH3 versus nitrogen reporting basis Makes composition interpretable and prevents incompatible concentration conventions from being compared.
- Water content
- Mass fraction or mg/kg, with method and detection limit Supports the anhydrous-versus-solution distinction and application-specific quality decisions.
- Temperature
- °C or K, with observation time and location Helps interpret phase, pressure, volatility and whether prior measurements remain applicable.
- Absolute pressure
- kPa absolute or bar absolute Supports interpretation of physical state and potential behaviour during pressure changes.
- Observed phase condition
- Gas; liquid; solid; liquid-vapour coexistence; other multiphase condition; unresolved Constrains sampling, transfer and interpretation of the material inventory.
- Aqueous speciation context
- pH and temperature, with free NH3 or total ammonia result and analytical definition; not applicable where no aqueous phase exists Prevents total ammonia from being treated as a direct measure of free NH3.
- Impurity profile
- Named constituents in mg/kg, mass fraction or another explicit basis, with detection limits Determines whether the material meets the requirements of its intended application.
- Containment and contact context
- Linked containment asset, wetted materials, connected receiving system and compatibility evidence Connects the ammonia condition to the equipment and substances involved in a proposed operation.
- Application qualification
- Unassessed; qualified for a named use; restricted; rejected; evidence expired Avoids treating a grade label as universal permission to use the material.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.ammonia-substance
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 36 questions.
Ammonia identity and material boundary Establishes what the ammonia designation refers to and which physical quantity or mixture is being assessed.
Ammonia, aqueous ammonia and ammonium-bearing materials cannot be treated as interchangeable identities.
NH3 identification
Separates chemical identity evidence from labels and nonspecific observations.
Evidence for ammonia identity
Records the basis for identifying NH3 and any unresolved alternatives.
- What evidence identifies NH3 rather than an ammonium salt, an amine or another alkaline material? definition
- Which supplier record, analytical result or other traceable evidence supports that identification? provenance
Anhydrous and mixture boundaries
Defines whether the subject is anhydrous ammonia, an aqueous solution or ammonia within another mixture.
Material referent and composition boundary
Makes the assessed material and the basis of its ammonia designation explicit.
- Does this record describe anhydrous ammonia, an aqueous solution or the ammonia component of another material? boundary
- What water-content evidence and applicable specification support any claim that the material is anhydrous? measurement
- Which batch, vessel contents, stream interval or sample does the identity evidence actually cover? boundary
Phase and aqueous speciation Describes ammonia's physical condition and, where water is present, the interpretation of dissolved ammonia measurements.
The same ammonia inventory can require different decisions depending on phase, pressure, temperature and aqueous speciation.
Physical state context
Relates observed phase to the conditions under which it was measured.
Phase and condition consistency
Records whether phase observations and operating conditions form a coherent account of the material.
- What phases are present, and what temperature and absolute pressure were recorded at the same location and time? measurement
- What validated property information supports interpreting this material as a single phase or a liquid-vapour inventory? provenance
- Could the proposed operation change phase, and which assessment must be completed before it proceeds? action
Dissolved ammonia interpretation
Distinguishes free NH3, ammonium and total ammonia in aqueous measurements.
Aqueous result basis
Captures the analytical and sample conditions needed to interpret an ammonia result in water.
- Does the result measure free NH3, ammonium or total ammonia, and is it reported as NH3 or as nitrogen? definition
- What pH, temperature and sample handling conditions accompany the result? measurement
- If free NH3 is calculated, what method and applicability limits support that calculation for this solution? provenance
Composition and use quality Establishes ammonia concentration, relevant impurities and fitness for a declared use.
A material described as ammonia may still be unsuitable for a particular refrigerant, reagent, feedstock or other application.
Assay and contamination
Connects composition measurements to representative samples and explicit reporting conventions.
Composition confidence
Records how well ammonia content and application-relevant contaminants are known.
- What ammonia concentration, water content and named impurity results are available, with units, uncertainty and detection limits? measurement
- How was the sample obtained and preserved to address ammonia loss or contamination before analysis? provenance
Application-specific acceptance
Relates measured quality to the requirements of the actual receiving process.
Declared use qualification
Keeps acceptance conditional on a named specification and current evidence.
- Which specification defines acceptable ammonia content, water and impurities for the intended use? provenance
- Do the available results justify acceptance, restriction, rejection or further sampling for that use? action
- What storage, transfer or contamination event would invalidate the current qualification? boundary
Containment, contact and release Connects ammonia condition to contact compatibility and evidence of escape from its intended boundary.
Handling decisions require evidence about the actual containment, contacted substances and release conditions, beyond the identity NH3.
Contact compatibility
Examines ammonia's contact with equipment materials and other substances under the recorded conditions.
Compatible contact evidence
Requires condition-specific support for wetted materials and possible chemical contact.
- Which metals, seals, lubricants and other materials contact this ammonia, and what evidence supports their compatibility at its composition and conditions? provenance
- Could this material contact acids, oxidising agents, cleaning chemicals or an unidentified residue? boundary
- Which compatibility gaps require the proposed connection or operation to be held? action
Release and exposure evidence
Records ammonia outside its intended containment and routes observations to relevant procedures.
Release status and measurement meaning
Distinguishes evidence of release from missing, limited or stale monitoring.
- What ammonia measurements or other observations indicate a release, and where and when were they obtained? measurement
- What detector range, calibration status and sampling limitations constrain interpretation of those observations? provenance
- Which applicable site procedure and verified trigger govern escalation or restriction of operations? action
Ammonia operation readiness Determines whether a specific operation is supported by the material evidence and receiving conditions.
Recognising ammonia does not establish that a particular transfer, dilution or use is permissible.
Transfer and conditioning
Assesses the material-side prerequisites for movement or deliberate changes in concentration or state.
Operation preconditions
Connects a proposed operation to ammonia-specific phase, composition and compatibility checks.
- Does the proposed operation involve gas, liquefied ammonia or aqueous ammonia, and what receiving conditions are specified? boundary
- What approved assessment addresses relevant pressure changes, phase changes and heat effects from dilution or absorption? provenance
- Which unresolved material conditions prevent the operation from being authorised? action
Decision validity and reassessment
Makes operational decisions conditional on the ammonia quantity and evidence to which they apply.
Conditional operation decision
Records the supported decision and the changes that require renewed assessment.
- For which ammonia quantity, intended use and operating conditions is the operation permitted, restricted or held? action
- Which change in concentration, water content, temperature, pressure, contamination or containment requires reassessment? boundary
- Which observations, specifications and responsible approval support the current decision? provenance
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.
- Anhydrous ammonia (compressed liquefied NH3)
- Aqueous ammonia / ammonium hydroxide solutions
- Fertilizer-grade anhydrous ammonia
- Refrigeration-grade ammonia (R-717)
- Electronic-grade / ultra-high-purity ammonia
- Reagent and ACS laboratory grades
- Household (dilute) aqueous ammonia
- Grey, blue, or green ammonia (same substance, distinguished by production carbon intensity)
- Which of these kinds and varieties hold for the sense of ammonia 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.
- Wikidata - Q4087 - Item for the chemical substance ammonia.
- CAS Registry Number - 7664-41-7 - Anhydrous ammonia; aqueous solutions are often indexed under the same CAS in commerce.
- EC / EINECS - 231-635-3 - European Community inventory number.
- PubChem CID - 222 - NCBI compound identifier.
- ChEBI - CHEBI:16134 - Chemical Entities of Biological Interest.
- UN number - UN 1005 (anhydrous); UN 2672 (aqueous, typically 10-35%) - Transport of dangerous goods; other UN numbers apply to some weaker or specialised solutions.
- Harmonized System - 2814.10 (anhydrous); 2814.20 (in aqueous solution) - HS heading 2814, ammonia, anhydrous or in aqueous solution.
- ASHRAE refrigerant number - R-717 - Closed-circuit refrigeration grade.
- InChIKey - QGZKDVFQNNGYKY-UHFFFAOYSA-N - Standard hashed InChI for NH3.
- Which of these identifiers and schemes hold for the sense of ammonia 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.
- OSHA 29 CFR 1910.1000 Table Z-1 - permissible exposure limit 50 ppm (35 mg/m³) TWA (U.S. Occupational Safety and Health Administration)
- NIOSH Recommended Exposure Limit 25 ppm TWA and 35 ppm STEL; IDLH 300 ppm (U.S. National Institute for Occupational Safety and Health)
- ACGIH TLV-TWA 25 ppm and TLV-STEL 35 ppm (American Conference of Governmental Industrial Hygienists)
- ANSI/CGA G-2.1 (historically ANSI K61.1) - Safety Requirements for the Storage and Handling of Anhydrous Ammonia (Compressed Gas Association / ANSI)
- IIAR 2 - Safe Design of Closed-Circuit Ammonia Refrigeration Systems (International Institute of Ammonia Refrigeration / ANSI)
- ASHRAE Standard 15 - Safety Standard for Refrigeration Systems (ASHRAE)
- CLP Regulation (EC) No 1272/2008 - GHS classification and labelling in the EU (European Commission)
- UN Model Regulations / ADR / IMDG - transport as UN 1005 or UN 2672 (UNECE / IMO)
- U.S. EPA CERCLA hazardous substance, reportable quantity 100 lb for anhydrous ammonia (U.S. Environmental Protection Agency)
- Which of these standards and regulation hold for the sense of ammonia 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.
- Haber-Bosch product used as the feedstock for urea, ammonium nitrate, ammonium sulfate and other nitrogen fertilizers (the large majority of world output).
- Injected as anhydrous liquid into soil in North American grain agriculture from nurse tanks.
- Industrial refrigerant R-717 in food cold stores, ice rinks, breweries and process chillers.
- Dilute aqueous cleaner (household 'ammonia').
- Intermediate for nitric acid, caprolactam/nylon, explosives, and many nitrogen chemicals.
- NOx control: injected or generated from urea in selective catalytic reduction on power plants and diesel exhaust.
- High-purity gas for silicon nitride and related CVD in semiconductor fabrication.
- Chloramination of drinking water (ammonia dosed with chlorine) and pH/alkalinity adjustment in process water.
- Which of these real-world use hold for the sense of ammonia 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.
- Normal boiling point - -33.33 - °C
- Melting point - -77.73 - °C
- Vapour pressure at 20 °C - 850-860 - kPa
- Liquid density at the normal boiling point - 680-685 - kg/m³
- pKa of conjugate acid NH4+ at 25 °C - 9.25 - pKa units
- Flammable range in air - 15-28 - vol%
- Commercial anhydrous purity - 99.5-99.995+ - % by mass NH3
- Industrial aqueous concentration - 24-30 - % w/w NH3
- Which of these typical measurements hold for the sense of ammonia 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.
- Acute inhalation injury with possible delayed pulmonary oedema; IDLH commonly cited at 300 ppm.
- Alkali chemical burns to eyes and moist skin; liquid anhydrous also causes cryogenic frostbite.
- Rapid flashing of liquefied gas from a failed tank, hose or refrigeration circuit, producing a dense toxic cloud.
- Fire or BLEVE of a pressure vessel if an ammonia inventory is heated in a fire and the mixture with air enters 15-28 vol%.
- Stress-corrosion cracking and attack of copper, brass, zinc and some steels in ammonia service if water, oxygen or residual stress are present.
- Violent incompatibility with halogens, hypochlorites, mercury, gold and silver compounds.
- Agricultural nurse-tank valve, hose and coupling failures during field application.
- Aquatic toxicity of unionized NH3 to fish, plus eutrophication once oxidised to nitrate.
- Which of these failure modes and hazards hold for the sense of ammonia 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.
- Direct anhydrous soil injection is common in the U.S. and Canadian Corn Belt; much of Europe and Asia delivers fertilizer nitrogen mainly as urea or ammonium nitrate because of storage, transport and major-accident rules.
- U.S. OSHA PEL remains 50 ppm TWA while NIOSH, ACGIH and many European occupational limits sit at 20-25 ppm TWA.
- Consumer 'household ammonia' strength and sale restrictions vary; some jurisdictions treat stronger solutions as dangerous goods.
- Labelling oscillates between 'ammonia solution' and 'ammonium hydroxide' even for the same aqueous grade.
- Trade talk of grey/blue/green ammonia is concentrated in energy-import policy (EU, Japan, Korea) and export projects (Australia, Middle East), not in fertilizer agronomy.
- Which of these regional variation hold for the sense of ammonia 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.
- Ammonium ion (NH4+) - Same nitrogen pool, different protonation state; the free-NH3 fraction is fixed by pH and temperature (pKa ≈ 9.25), not by a separate substance identity.
- Methylamine and other volatile amines - Similar fishy/pungent odour; separate by GC, specific sensors, or the absence of the NH3 InChIKey/CAS 7664-41-7.
- Urea - Solid CO(NH2)2 fertilizer that hydrolyses to ammonia in soil or SCR systems; dry urea does not present NH3 vapour pressure of anhydrous ammonia.
- Hydrazine (N2H4) - Also a reduced N-H compound and reducing agent, but liquid at ambient temperature (bp ≈ 114 °C) with CAS 302-01-2, not 7664-41-7.
- Chloramine (NH2Cl) - Water-treatment relative formed when ammonia meets free chlorine; distinguished by combined-chlorine methods, not by NH3 gas detection alone.
- Liquefied petroleum gas in agricultural tanks - Nurse tanks can look similar; ammonia is identified by its sharp odour, ~8.5 bar vapour pressure at 20 °C, water solubility, and copper-alloy incompatibility.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of ammonia this model covers, and on what evidence? provenance
Sources
- Compound Summary for CID 222, Ammonia - NCBI PubChem, National Library of Medicine - Identity (CAS, InChIKey, molecular formula), physical constants, GHS classification, and common uses.
- Ammonia (CAS 7664-41-7) - NIST Chemistry WebBook, National Institute of Standards and Technology - Evaluated boiling point, melting point, critical constants, vapour pressure, and thermochemistry.
- Pocket Guide to Chemical Hazards: Ammonia - National Institute for Occupational Safety and Health (CDC/NIOSH) - Occupational exposure limits, IDLH, physical description, incompatibilities, and inhalation/contact hazards.
- Ammonia - Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH - Haber-Bosch manufacture, commercial grades, fertilizer and downstream chemical uses, handling practice, and materials of construction.
What the second pass must settle
- Does an existing Vercy world model already own ammonia or any part of this concept, requiring linkage instead of a separate publication?
- Where should ownership pass from this ammonia model to a mixture model for aqueous products and multicomponent streams?
- Which authoritative specifications define anhydrous status and application grades, including their water and impurity limits?
- Which validated property and aqueous-speciation methods cover the concentrations, temperatures and pressures required by intended users?
- Which jurisdictional requirements, compatibility references and site procedures should govern operation-specific restrictions and release triggers?