diff --git a/offpele/solvent/solvent.py b/offpele/solvent/solvent.py
index 7134f984..217429bc 100644
--- a/offpele/solvent/solvent.py
+++ b/offpele/solvent/solvent.py
@@ -88,6 +88,7 @@ def to_dict(self):
 
         for atom, name in zip(self.molecule.rdkit_molecule.GetAtoms(),
                               atom_names):
+            name = name.replace(' ', '_')
             index = atom.GetIdx()
             data['SolventParameters'][self.molecule.name][name] = \
                 {'radius': round(self.radii[tuple((index, ))].value_in_unit(