| id | 0..1 | string | Logical id of this artifact |
| meta | 0..1 | Meta | Metadata about the resource |
| implicitRules | 0..1 | uri | A set of rules under which this content was created |
| language | 0..1 | code | Language of the resource content |
| text | 0..1 | Narrative | Text summary of the resource, for human interpretation |
| contained | 0..* | Resource | Contained, inline Resources |
| extension | 0..* | Extension | Additional content defined by implementations |
| modifierExtension | 0..* | Extension | Extensions that cannot be ignored |
| identifier | 0..1 | Identifier | Identifier by which this substance is known |
| type | 0..1 | CodeableConcept | High level categorization, e.g. polymer or nucleic acid |
| status | 0..1 | CodeableConcept | Status of substance within the catalogue e.g. approved |
| domain | 0..1 | CodeableConcept | If the substance applies to only human or veterinary use |
| description | 0..1 | string | Textual description of the substance |
| source | 0..* | Reference | Supporting literature |
| comment | 0..1 | string | Textual comment about this record of a substance |
| moiety | 0..* | BackboneElement | Moiety, for structural modifications |
| property | 0..* | BackboneElement | General specifications for this substance, including how it is related to other substances |
| referenceInformation | 0..1 | Reference | General information detailing this substance |
| structure | 0..1 | BackboneElement | Structural information |
| code | 0..* | BackboneElement | Codes associated with the substance |
| name | 0..* | BackboneElement | Names applicable to this substance |
| molecularWeight | 0..* | | The molecular weight or weight range (for proteins, polymers or nucleic acids) |
| relationship | 0..* | BackboneElement | A link between this substance and another, with details of the relationship |
| nucleicAcid | 0..1 | Reference | Data items specific to nucleic acids |
| polymer | 0..1 | Reference | Data items specific to polymers |
| protein | 0..1 | Reference | Data items specific to proteins |
| sourceMaterial | 0..1 | Reference | Material or taxonomic/anatomical source for the substance |