diff --git a/disciplines/periodictable.py b/disciplines/periodictable.py
index 7e36b7b7..d356fbba 100755
--- a/disciplines/periodictable.py
+++ b/disciplines/periodictable.py
@@ -39,7 +39,7 @@ def en(s):
 
 # Create new ontology
 onto = world.get_ontology('http://emmo.info/emmo/disciplines/periodictable#')
-onto.iri = 'http://emmo.info/emmo/disciplines/periodictable#'
+onto.iri = 'http://emmo.info/emmo/disciplines/periodictable'
 onto.base_iri = 'http://emmo.info/emmo#'
 onto.prefix = 'emmo'
 onto.imported_ontologies.append(perceptual)
diff --git a/disciplines/periodictable.ttl b/disciplines/periodictable.ttl
index 97ca2480..f9ee2c05 100644
--- a/disciplines/periodictable.ttl
+++ b/disciplines/periodictable.ttl
@@ -1657,7 +1657,7 @@
         :EMMO_eb77076b_a104_42ac_a065_798b2d2809ad ;
     skos:prefLabel "MagnesiumAtom"@en .
 
-<http://emmo.info/emmo/disciplines/periodictable#> a owl:Ontology ;
+<http://emmo.info/emmo/disciplines/periodictable> a owl:Ontology ;
     dcterms:abstract "The periodic table domain ontology provide a simple reference implementation of all atoms in the periodic table with a few selected conventional properties.  It is ment as both an example for other domain ontologies as well as a useful assert by itself. Periodic table is released under the Creative Commons Attribution 4.0 International license (CC BY 4.0)."@en ;
     dcterms:creator "Emanuele Ghedini, University of Bologna, IT"@en,
         "Francesca Lønstad Bleken, SINTEF, NO"@en,
@@ -2519,4 +2519,3 @@
     rdfs:domain :EMMO_eb77076b_a104_42ac_a065_798b2d2809ad ;
     rdfs:range xsd:integer ;
     skos:prefLabel "hasAtomicNumber"@en .
-