diff --git a/dumux/material/fluidsystems/h2on2o2.hh b/dumux/material/fluidsystems/h2on2o2.hh
index 71477f94c1086fe8f315e211bfb8b1fce4abaddc..01cc92d7a57defe3f2ac39bed6ce80fa819460a3 100644
--- a/dumux/material/fluidsystems/h2on2o2.hh
+++ b/dumux/material/fluidsystems/h2on2o2.hh
@@ -838,7 +838,7 @@ public:
             Scalar c_pH2Omolar = Dumux::Constants<Scalar>::R + c_vH2Omolar;
 
             c_pN2 = c_pN2molar/molarMass(N2Idx);
-            c_pN2 = c_pO2molar/molarMass(O2Idx);
+            c_pO2 = c_pO2molar/molarMass(O2Idx);
             c_pH2O = c_pH2Omolar/molarMass(H2OIdx);
         }