diff --git a/modules/conop/src/standard_compounds.cc b/modules/conop/src/standard_compounds.cc
index 5d9f21c9051009c78bbada8f19ecb2a76097fe87..8d60721084d011b9653dc1a0ae33af415b934a08 100644
--- a/modules/conop/src/standard_compounds.cc
+++ b/modules/conop/src/standard_compounds.cc
@@ -1133,7 +1133,7 @@ CompoundPtr MakeGCompound() {
 CompoundPtr MakeTCompound() {
   CompoundPtr c( new Compound("T"));
   c->SetOneLetterCode('T');
-  c->SetChemClass(mol::ChemClass('S'));
+  c->SetChemClass(mol::ChemClass('R'));
   c->SetChemType(mol::ChemType('U'));
   c->SetFormula("C10 H15 N2 O8 P");
   AtomSpec atoms[] = {