To represent a datatype value with more than one aspect
Extension
The original value is reified (decomposed) in all the neccesary data type properties and values
The first step is to choose the datatype value that needs to be reified and create a class for it (e.g. StandardWaterBoilingPoint), then add a restriction (e.g. [Water HasBoilingPoint some StandardWaterBoilingPoint]) and all the neccesary datatype properties and restrictions to the reified class (e.g. [StandardWaterBoilingPoint partial HasUnit value celsius], [StandardWaterBoilingPoint partial HasValue value 100], etc.)
Numerical values can have different aspects. For example, a boiling point has a temperature value, a pressure, etc. This simple ODP should be used to model those cases
Nary DataType Relationship
Bijan Parsia and Michael Smith. Quantities in OWL. OWLed 2008 EU
Nary Relationship
After the reification a value with different aspects is represented in the ontology