Hydrates and anhydrous substances
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Modeling
Parent concept
Most distal appropriate descendant of 105590001 |Substance (substance)|
Semantic tag
(substance)
Definition status
Primitive
Attribute
738774007 |Is modification of (attribute)| relationship to the substance with unspecified hydration
726542003 |Has disposition (attribute)|, as appropriate
Hydrates
Hydates are modeled with an 738774007 | Is modification of (attribute)| relationship to the substance with unspecified hydration.
For example,
Ferrous oxalate dihydrate (substance) is modification of → Ferrous oxalate
Caffeine hydrate (substance) is modification of → Caffeine
Zinc sulfate heptahydrate (substance) is modification of → Zinc sulfate
Naming
FSN
Pattern:
X hydrate (substance)
X dihydrate (substance)
X monohydrate (substance)
For example,
Copper sulfate pentahydrate (substance)
Preferred Term
Pattern:
X hydrate
X dihydrate
X monohydrate
For example,
Copper sulfate pentahydrate
Exemplar
The following illustrates the inferred view.
Caffeine hydrate (substance) IS MODIFICATION OF Caffeine (substance)
Anhydrous compounds
Anhydrous compounds have an 738774007 | Is modification of (attribute)| relationship to the unspecified substance, i.e., where the level hydration is not specified.
For example,
Sodium carbonate anhydrous (substance) is modification of → Sodium carbonate
Theophylline anhydrous (substance) is modification of → Theophylline
Naming Guidelines
FSN
Pattern:
X anhydrous (substance)
For example,
Theophylline anhydrous (substance)
Preferred Term
Pattern:
X anhydrous
For example,
Theophylline anhydrous
Synonyms
Anhydrous X
Exemplar
The following illustrates the inferred view.
|Theophylline anhydrous (substance)| IS MODIFICATION OF |Theophylline (substance)|
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