## Chemistry

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Last Update: 4/5/02
Copyright© 1996-2002. All rights reserved. See Terms of Usage.

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At the present time, Cyc's representation of scientific chemistry is limited to certain basic relations between atoms, molecules, and substances. Most representations of complex substances in Cyc do not include chemical structures and formulae, or the axioms to reason about them. Rather, substances and their properties are represented at a more "everyday" level: creation, destruction, changes, and interactions are described and reasoned about, but the underlying mechanisms are not usually considered.

We have resisted the temptation to assert many detailed, ready-made axioms based on chemical reference material listing atomic weights, electronegativity values, chemical formulae, etc., because devising the supporting theoretical axioms to use those facts is neither easy nor of obvious value. Such is the case with many fundamental theories in science: connecting them to the real world is so hard that most scientific problems are solved by invoking more specific rules which apply to different kinds of situations.

The following constants and the representational techniques they embody may serve as a starting point for more complete representations of chemical substances as well as a more comprehensive chemical theory. For example, the functional specification of types of atoms and nuclei can be extended to cover isotopes.

### Elements And Atoms

#$ElementStuff chemical elements **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of tangible substances; a subcollection of #$InanimateThing. Every instance of #$ElementStuff is a piece of tangible stuff, composed of a quantity of atoms, all of which are of the same chemical element. That is, every atom in an individual piece of #$ElementStuff has the same number of protons in its atomic nucleus as does every other atom in that piece. For example, all pieces of carbon are instances of #$ElementStuff. All pieces of two of #$Carbon's subcollections, #$Diamond and #$Graphite, also are instances of #$ElementStuff. On the other hand, instances of #$Water, because they are constituted of both (some) #$Hydrogen and (some) #$Oxygen atoms, do not belong to the collection #$ElementStuff.
> guid: bd5908b9-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TangibleStuffCompositionType
> direct specialization of: #$InanimateThing
> direct generalization of: #$UnalloyedMetal #$NobleGas

#$ElementStuffTypeByNumberOfProtons types of chemical element classified by number of protons **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of collections. #$ElementStuffTypeByNumberOfProtons partitions the collection #$ElementStuff. Each instance of #$ElementStuffTypeByNumberOfProtons is a subset of #$ElementStuff which is defined ONLY by the atomic composition of its instances -- neither the isotopic composition or physical state of the substances, nor any other additional feature, determines membership in a collection which #$isa #$ElementStuffTypeByNumberOfProtons. All that matters is that the instances of that type (i.e., collection) of stuff are entirely composed of atoms having a particular number of protons in each atomic nucleus. Thus, the collection #$Carbon is an instance of #$ElementStuffTypeByNumberOfProtons, but neither the collection #$Diamond nor the collection #$Graphite is (even though they are subcollections of #$Carbon), because their members have additional qualifications.
> guid: bd590830-9c29-11b1-9dad-c379636f7270
> direct instance of: #$SecondOrderCollection #$DisjointCollectionType
> direct specialization of: #$ChemicalCompoundType #$ElementStuffType

#$atomicNumber atomic number **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> The predicate #$atomicNumber indicates the atomic number of a type of element. (#$atomicNumber E N) means that E, a collection belonging to #$ElementStuffTypeByNumberOfProtons, has the positive integer N for its atomic number. This means that any instance of (#$AtomFn E) must have N #$Protons in its #$AtomicNucleus. For example, (#$atomicNumber #$Carbon 6), and every instance of (#$AtomFn #$Carbon) has six protons in its nucleus.
> guid: bd5890dc-9c29-11b1-9dad-c379636f7270
> direct instance of: #$FunctionalSlot

#$AtomFn atom fn **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> An instance of #$CollectionDenotingFunction. #$AtomFn may be used to denote any subcollection of #$Atom which contains all the atoms of a particular element type. #$AtomFn takes an instance of #$ElementStuffTypeByNumberOfProtons as its single argument and returns the collection of all atoms of that element. Thus, for any E which is an #$ElementStuffTypeByNumberOfProtons, (#$AtomFn E) returns the subcollection of #$Atom which contains all the atoms of element type E. Each atom in the collection (#$AtomFn E) has N protons in its atomic nucleus, where N is the #$atomicNumber of the element type E. For example, (#$AtomFn #$Carbon) is the collection of carbon atoms, each of which has 6 protons in its nucleus.
> guid: c0fcf284-9c29-11b1-9dad-c379636f7270
> direct instance of: #$CollectionDenotingFunction #$UnaryFunction #$ReifiableFunction #$Individual

#$Atom atoms **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of microscopic-scale objects. Each instance of #$Atom has one atomic nucleus and some number of electrons. As a default, we assume that an instance of #$Atom has no net charge, i.e., that it has as many instances of #$Electrons as it does of #$Protons in its #$AtomicNucleus; but note there are exceptions, e.g., those which are instances of #$Ion.
> guid: bd5891ef-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$ChemicalObject

#$NucleusFn nucleus fn **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> #$NucleusFn is a Cyc function, specifically a #$CollectionDenotingFunction. #$NucleusFn takes an instance of #$ElementStuffTypeByNumberOfProtons (q.v.) as its single argument and returns a collection of all the atomic nucleii belonging to element-stuff of that type. Thus, (#$NucleusFn E) denotes a subcollection of #$AtomicNucleus whose elements all have the same number of protons. For example, (#$NucleusFn #$Carbon) is the collection of #$Carbon nuclei, each of which has six protons.
> guid: c0fcee23-9c29-11b1-9dad-c379636f7270
> direct instance of: #$UnaryFunction #$CollectionDenotingFunction #$ReifiableFunction #$Individual

#$AtomicNucleus atomic nuclei **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of objects; a subcollection of #$MicroscopicScaleObject. Each instance of #$AtomicNucleus is an object composed of some definite number of instances of #$Proton and some definite number of instances of #$Neutron. Instances of the collection #$Atom are each composed of one member of #$AtomicNucleus and some number of electrons.
> guid: bd58a3d9-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$MicroscopicScaleObject

### Sub

#$SubAtomicParticle subatomic particles **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of objects; a subcollection of #$MicroscopicScaleObject. Every instance of #$SubAtomicParticle is a physical particle smaller than an atom. Major subcollections of #$SubAtomicParticle include #$Electron, #$Proton, and #$Neutron.
> guid: bd58db74-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$MicroscopicScaleObject #$InanimateObject-Natural
> direct generalization of: #$Nucleon #$Electron

#$Electron electrons **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of objects; a subcollection of #$SubAtomicParticle. Every instance of #$Electron is a subatomic particle with an #$ElectricalCharge of -1.
> guid: bd5881d3-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$SubAtomicParticle

#$Nucleon nucleons **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of objects; a subcollection of #$SubAtomicParticle. Each instance of #$Nucleon is a subatomic particle normally found in some atomic nucleus. #$Nucleon has two subcollections, #$Proton and #$Neutron. Every instance of #$AtomicNucleus is composed of some number of #$Nucleons.
> guid: bd588191-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$SubAtomicParticle
> direct generalization of: #$Neutron #$Proton

#$Proton protons **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of objects; a subcollection of #$Nucleon. Each instance of #$Proton is a nucleon which has an #$ElectricalCharge of +1.
> guid: bd58814d-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$Nucleon

#$Neutron neutrons

> A specialization of #$Nucleon. Each instance of #$Neutron is a nucleon with an electrical charge of 0.
> guid: bd588216-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$Nucleon

### Chemical Compounds Molecules

#$ChemicalObject chemical objects **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A specialization of #$MicroscopicScaleObject. Each instance of #$ChemicalObject is an object whose behavior is typically described in terms of its outer cloud of #$Electrons. Specializations of #$ChemicalObject include the collections #$Atom, #$Molecule, and #$Ion.
> guid: bd58916a-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$MicroscopicScaleObject
> direct generalization of: #$Molecule #$Atom

#$Molecule molecules **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of microscopic-scale objects; a subcollection of #$ChemicalObject. Every instance of #$Molecule is a microscopic object whose component atoms are all chemically bonded to each other; typically, this means that the atoms are covalently bonded. Examples: some instances of #$Molecule, including molecules of oxygen (O2), ozone (O3), water (H2O), carbon monoxide (CO), carbon dioxide (CO2), etc., contain covalently bonded atoms belonging to the collection #$Oxygen. Some highly complex examples of #$Molecule are those belonging to the collection #$DNAMolecule. See also #$MoleculeFn. Note: #$Diamond and other macroscopic covalent solids are excluded from belonging to #$Molecule by the constraint that instances of #$Molecule are microscopic.
> guid: bd58f0b2-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$ComplexPhysicalObject #$ChemicalObject

#$Ion ions **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of microscopic-scale objects; a subset of #$ChemicalObject. Every instance of #$Ion is an atom or radical which has either a negative or positive net electrical charge, due to having either more or fewer electrons than there are protons in its nuclei. Note: atomic ions violate Cyc's default assumption that instances of #$Atom have a net electrical charge of zero, so #$Ion constitutes a class of exceptions to that rule.
> guid: c0fbae39-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ExistingObjectType
> direct specialization of: #$ChemicalObject

#$ChemicalCompoundType chemical compounds **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of collections; a specialization of #$TangibleStuffCompositionType. Every instance of #$ChemicalCompoundType is a specialization of #$PartiallyTangible whose instances are defined ONLY by their chemical composition, and not by their physical state or any other property. In Cyc's current representation, #$ChemicalCompoundTypes can be of two varieties: (1) Collections whose instances are completely uniform with each other in terms of chemical composition; this includes (a) the chemical elements -- such as #$Carbon, #$Oxygen, and #$Hydrogen -- which are instances of #$ElementStuffTypeByNumberOfProtons (thus, the latter is a specialization of #$ChemicalCompoundType), and (b) compounds constituted of more than one substance chemically bonded, e.g., #$Water, #$Caffeine, and #$IronOxide. (2) Substances which have a general chemical specification, that is, whose instances do not have exactly the same chemical composition but fall within certain specifications, e.g., #$DNAStuff. Cyc's current theory includes those cases in #$ChemicalCompoundType, though they are arguably borderline. (Future work may require the creation of type collections to identify various levels of chemical specification, such as `exact formula' or `exact structure'.) Note: Collections which Cyc does NOT classify as #$ChemicalCompoundTypes include collections of substances which have some component which is of overriding significance in some context, so that in everyday language such substances are frequently referred to by the name of their important component (e.g., `penicillin' applied to a tablet containing penicillin), but which have significant admixtures of other substances. Our representation distinguishes between the chemical compound (here, instances of #$Penicillin) and the mixture of substances in a tablet containing some #$Penicillin for pharmaceutical use. Thus, #$Penicillin is an instance of #$ChemicalCompoundType, but the collection of tablets containing penicillin and including other ingredients are not. Also, specializations of #$Mixture, such as #$Lemonade, are not instances of #$ChemicalCompoundType, because mixtures are determined by their physical state rather than solely by their chemical composition.
> guid: bd58cd95-9c29-11b1-9dad-c379636f7270
> direct instance of: #$SiblingDisjointCollection #$SecondOrderCollection
> direct specialization of: #$TangibleStuffCompositionType
> direct generalization of: #$ElementStuffTypeByNumberOfProtons

#$MolecularStuff molecular stuff **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of tangible stuff. Every instance of #$MolecularStuff is a portion of stuff composed of covalently-bonded molecules. Thus, #$Water and #$DNAStuff are subcollections of #$MolecularStuff; each of their instances consists of covalently bonded molecules. But instances of #$Salt-NaCl are not examples of #$MolecularStuff. Also, #$Oxygen is not a subcollection of #$MolecularStuff, since #$Oxygen denotes anything composed of that element, not just O2 (molecular oxygen) and O3 (ozone).
> guid: bd59e38c-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TangibleStuffCompositionType
> direct specialization of: #$PartiallyTangible

#$MoleculeFn molecule fn **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> #$MoleculeFn is a Cyc function, specifically a #$CollectionDenotingFunction. It takes an instance of #$ChemicalCompoundType as its sole argument and returns the set of all molecules of that compound. (#$MoleculeFn X) denotes the collection of all #$Molecules of #$MolecularStuff X. For example, (#$MoleculeFn #$Water) is the collection of all water molecules.
> guid: c0fcede2-9c29-11b1-9dad-c379636f7270
> direct instance of: #$UnaryFunction #$CollectionDenotingFunction #$MacroRelation #$ReifiableFunction #$Individual

#$MicroscopicScaleObject microscopic objects **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A specialization of #$PartiallyTangible. Each instance of #$MicroscopicScaleObject is a partially tangible object which is so small that human beings cannot perceive it, except (perhaps) with the use of special devices such as electron microscopes. Specializations of #$MicroscopicScaleObject include #$Molecule, #$Atom, #$SubAtomicParticle, #$Chloroplast, and #$Mitochondrion.
> guid: bd5891ac-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TemporalStuffType
> direct specialization of: #$PartiallyTangible
> direct generalization of: #$SubAtomicParticle #$ChemicalObject #$AtomicNucleus #$CellPart #$Microorganism

### Metal

#$Metal metallic elements **GAFs NOT REVIEWED**

> An instance of #$TangibleStuffCompositionType. Every instance of #$Metal is a tangible object having certain characteristic physical and chemical properties. Instances of #$Metal are good conductors of electricity and heat, and most instances of #$Metal are solids at room temperature (although all instances of #$Mercury, for example, are liquids at room temperature). Solid instances of #$Metal have a shiny luster, and are highly malleable. Specializations of #$Metal includes #$Mercury, #$Potassium, #$Brass, #$Lead, and #$Iron.
> guid: bd58ac39-9c29-11b1-9dad-c379636f7270
> direct instance of: #$ProductByGenericType #$TangibleStuffCompositionType
> direct specialization of: #$ElectricalConductor #$InorganicStuff
> direct generalization of: #$UnalloyedMetal #$MetalAlloy

#$MetalAlloy alloys **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of tangible stuffs; a subcollection of #$Metal. Each instance of #$MetalAlloy is a metallic stuff which is a homogeneous blend of at least one part of #$UnalloyedMetal with at least one other substance. #$MetalAlloy is not a subcollection of #$Mixture, because each instance of #$MetalAlloy is defined not only by the amounts and kinds of its #$constituents, but also (unlike a mixture) by the internal structures formed during its creation. Furthermore, the creation process is typically more complex than #$Mixing. Common metal alloys include the instances of #$Bronze-Stuff, #$Brass, and #$Steel. Note that #$GalvanizedMetal is NOT a subcollection of #$MetalAlloy, because every instance of #$GalvanizedMetal has a coating of some #$Zinc on its surface, and thus (unlike an alloy) the components of galvanized metals are not homogenously distributed throughout.
> guid: bd58cc8b-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TangibleStuffCompositionType
> direct specialization of: #$Mixture #$ArtificialMaterial #$Metal

#$UnalloyedMetal unalloyed metals **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of tangible stuffs; a subcollection of #$Metal. Every instance of #$UnalloyedMetal is a metal which is also an element, i.e., a substance of unmixed chemical type. Thus, each subcollection of #$UnalloyedMetal is a subcollection of both #$Metal and #$ElementStuff. Examples of #$UnalloyedMetal include #$Gold, #$Iron, #$Uranium, #$Antimony, #$Titanium, and many more.
> guid: bd5908f8-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TangibleStuffCompositionType
> direct specialization of: #$Metal #$ElementStuff

#$NobleGas inert gases

> A specialization of #$ElementStuff. Each specialization of #$NobleGas is a type of element that does _not_ readily form compounds with other types of elements. Instances of #$NobleGas are highly stable, due to the fact that they have the maximum number of electrons possible in their outer shell. The six specializations of #$NobleGas are #$Helium, #$Neon, #$Argon, #$Krypton, #$Xenon, and #$Radon.
> guid: bd58c01f-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TangibleStuffCompositionType
> direct specialization of: #$ElementStuff

### Chemical Reactions

#$ChemicalReaction chemical reactions **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of events; a subcollection of #$TransformationEvent. Each instance of #$ChemicalReaction is an event in which two or more substances undergo a chemical change, i.e., some portions of the substances involved are transformed into different #$ChemicalCompoundTypes. The transformations are brought about by purely chemical (including biochemical) means which affect chemical bonds between atoms in the molecules of stuff, rather than by physical means, biological means, or purposeful planning, etc. Examples of #$ChemicalReaction: instances of #$CombustionProcess; instances of #$Photosynthesis-Generic.
> guid: bd589bc8-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TemporalObjectType #$DefaultDisjointScriptType
> direct specialization of: #$ChemicalInteraction #$TransformationEvent

#$catalyst catalyzer (actor slot) **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> The predicate #$catalyst identifies the particular thing that acts as a catalyst in a particular chemical reaction. (#$catalyst R X) means that the #$ChemicalReaction R has the particular quantity of substance X as a catalyst. For example, every instance of #$Photosynthesis-Generic has some portion of #$Chlorophyll as a catalyst; an amount of #$Water may be a #$catalyst in some #$OxidationProcess of a #$Metal.
> guid: be011804-9c29-11b1-9dad-c379636f7270
> direct instance of: #$IndividualLevelPredicate #$ActorSlot
> direct specialization of: #$unchangedActors

### Purity

#$PureFn pure fn **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> An instance of #$CollectionDenotingFunction. (#$PureFn X) denotes the subcollection of the #$ChemicalCompoundType X whose instances are chemically pure. Note that #$PureFn can be applied only to instances of #$ChemicalCompoundType (such as #$Fructose or #$Water), but not to mixtures (such as #$Air). See also #$PureCompound.
> guid: c0fbb1ad-9c29-11b1-9dad-c379636f7270
> direct instance of: #$UnaryIntersectionFunction #$Individual

#$PureCompound pure compounds **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of tangible stuffs. Each instance of #$PureCompound is a chemically pure portion of stuff belonging to some particular #$ChemicalCompoundType (e.g., #$Carbon, #$Water, #$Cellulose ). `Chemically pure' applies to a piece of stuff which has no sub-portions that fail to conform to the chemical composition of its (single) #$ChemicalCompoundType. In typical contexts, most common portions of a #$ChemicalCompoundType will not be instances of #$PureCompound . For example, a piece of pencil lead, though mostly carbon, will not be an instance since it is not pure carbon and any portion of ordinary tap water will contain too many impurities. Many sub-portions of either a piece of pencil lead or portion of tap water will fail to conform to the chemical composition of either carbon or water. Some instances of #$ChemicalCompoundType are subcollections of #$PureCompound in most contexts but not in all. In typical domestic contexts, for example, a piece of ordinary distilled water would be an instance of #$PureCompound . However, in a clean room or microchip manufacturing context, ordinary distilled water would probably be considerd impure (see #$ImpureCompound). In general, to refer to a pure instance of a substance one can use the function #$PureFn, e.g. (#$PureFn #$Carbon). Note that #$PureFn has #$PureCompound as a #$resultGenl . Since this kind of purity is relative to specified chemical composition only, #$PureCompound (and #$PureFn) does not pertain to mixtures in Cyc (such as #$Air). Cf. #$Mixture, #$ChemicalCompoundType. See also #$PureCompoundType and #$ImpureCompound.
> guid: c0fbb161-9c29-11b1-9dad-c379636f7270
> direct instance of: #$TangibleStuffCompositionType
> direct specialization of: #$InanimateThing

#$PureCompoundType types of pure chemical compound **COMMENT NOT REVIEWED** **GAFs NOT REVIEWED**

> A collection of collections. Every instance of #$PureCompoundType is a collection which is a subcollection of both #$PureCompound and of some particular #$ChemicalCompoundType (e.g., #$Carbon, #$Water, #$Cellulose). Each instance of #$PureCompoundType is defined ONLY by the properties of its #$ChemicalCompoundType, and of #$PureCompound (q.v.). For example, (#$PureFn #$Fructose) is an instance of #$PureCompoundType, but the subcollections of #$Fructose, such as (say) `pure fructose derived from honey' would not be instances of #$PureCompoundType.
> guid: c0fbb120-9c29-11b1-9dad-c379636f7270
> direct instance of: #$SecondOrderCollection
> direct specialization of: #$TangibleStuffCompositionType

Copyright© 1996-2002. All rights reserved. See Terms of Usage.