diff --git a/diffusivityModel/diffusivityModel/diffusivityModel.C b/diffusivityModel/diffusivityModel/diffusivityModel.C
index 83f0dd9..83135e6 100644
--- a/diffusivityModel/diffusivityModel/diffusivityModel.C
+++ b/diffusivityModel/diffusivityModel/diffusivityModel.C
@@ -25,6 +25,8 @@ License
 
 #include "diffusivityModel.H"
 
+#include <cmath>
+
 #include "IFstream.H"
 #include "speciesTable.H"
 #include "volFieldsFwd.H"
@@ -74,7 +76,8 @@ Foam::diffusivityModel::mixAvgDi(UList<scalar>& Di, const scalarSymmetricSquareM
     label pureSpecieI = -1;
     forAll (X, i)
     {
-        if (1. - X[i] < 1e-12)
+        if (1. - X[i] < 1e-12 || std::isinf(X[i]/(1.-Y[i])))
+            
         {
             pureSpecieI = i;
             pure = true;