Material Element	Neuroscience Information Framework (NIF) Standard Ontology	Source
http://sweet.jpl.nasa.gov/2.3/matrElement.owl#Chalcogen	http://purl.obolibrary.org/obo/CHEBI_33303	LOOM
http://sweet.jpl.nasa.gov/2.3/matrElement.owl#Halogen	http://purl.obolibrary.org/obo/CHEBI_24473	LOOM
http://sweet.jpl.nasa.gov/2.3/matr.owl#Chemical	http://uri.neuinfo.org/nif/nifstd/nlx_chem_20090203	LOOM