Dear all,
I am in the process of linking an ontology to some of the chemical compounds and elements in DBPedia. This is particularly useful since DBPedia records the INCHI numbers of these instances (International Chemical key by the IUAPC). However, I am unable to retrieve that information concerning chemical elements. The SPARQL endpoint returns empty results whenever I query for dbo:ChemicalElement instances, for example:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX dbo: <http://dbpedia.org/ontology/>
SELECT * WHERE { ?y a dbo:ChemicalElement . }
Are these absent from the knowledge graph? Or should they be queried in a different way?
Thank you.