Proposal of new properties for ChemicalSubstance in order to create a new UseCase

[gorbondiga]

Regarding the UseCase of ChemicalSubstance, I would like to use it as a property of a hypothetical Crystallization Experiment BioSchema. Thus, I believe that by adding few properties (see below) to ChemicalSubstance, it could be used, with MANY cardinality as a Chemical Solution in other possible experimental BioSchema.

New proposed properties

• concentration; The quantity of solute present in a given quantity of solution. ONE
• unitOfMeasure; A named quantity in terms of which other quantities are measured or specified, used as a standard measurement of like kinds. ONE
• CASnumber; A unique numerical identifier assigned, by the Chemical Abstract Service (CAS), a division of the American Chemical Society, to chemical compounds, polymers, biological sequences, mixtures, and alloys. ONE
• molecularWeight; This is the molecular weight of the entity being described, not of the parent. Units should be included in the form. ONE
• pH Quantity of dimension one used to express on a scale from 0 to 14 the amount-of-substance concentration of hydrogen ion of dilute aqueous solution, calculated as the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter. ONE

Example
{"ChemicalSubstance":
[
{
"@type": "ChemicalSubstance",
"@id": "",
"name": "Lithium sulfate",
... ,
"concentration": "0.2",
"unitOfMeasure": "M",
"pH": "",
"url: "https://www.ebi.ac.uk/chebi/chebiOntology.do?chebiId=CHEBI:53474&treeView=true",
"CASnumber": "10102-25-7"
},
{
"@type": "ChemicalSubstance",
"@id": "",
"name": "Tris",
... ,
"concentration": "0.1",
"unitOfMeasure": "M",
"pH": "8.5",
"url": "https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:9754",
"CASnumber": "77-86-1"
}
]
}

[sneumann]

Hi, thanks for opening the issue and get the discussion rolling. With @egonw and @meier-rene we recently discussed stuff around ChemicalSubstance.
Here are some (unsorted) thoughts:

• Some properties could go up in the hierarchy to BioChemEntity, e.g. concentration. If the concentration is represented as https://schema.org/PropertyValue this can directly specify the Unit as well. If possible, units should be sourced from ontologies, e.g. https://www.ebi.ac.uk/ols4/ontologies/uo/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FUO_1000062?lang=en
• Maybe the same applies to pH ?
• The CAS is an identifier. So you could readily add it similar to the examples in https://schema.org/identifier (go down to the Example1 and use JSON-LD Tab to easily see what I mean).
• the molecularWeight is already a property of the https://schema.org/MolecularEntity, and for ChemicalSubstance I have the feeling would be difficult to describe, what in case of a Polymer distribution ? What about Crystals ?
• Something you didn't have in your above suggestion is the role of a ChemicalSubstance. Tris is probably a buffer, this could be added as a DefinedTerm.

Yours,
Steffen