diff --git a/src/Backends/Helmholtz/MixtureParameters.cpp b/src/Backends/Helmholtz/MixtureParameters.cpp
index 43430444..7fb0e798 100644
--- a/src/Backends/Helmholtz/MixtureParameters.cpp
+++ b/src/Backends/Helmholtz/MixtureParameters.cpp
@@ -165,9 +165,9 @@ std::string get_mixture_binary_pair_data(const std::string &CAS1, const std::str
             if (key == "name1"){ return v[0].get_string("name1"); }
             else if (key == "name2"){ return v[0].get_string("name2"); }
             else if (key == "BibTeX"){ return v[0].get_string("BibTeX"); }
-            else if (key == "F"){ return v[0].get_string("F"); }
             else if (key == "function"){ return v[0].get_string("function"); }
             else if (key == "type"){ return v[0].get_string("type"); }
+            else if (key == "F"){ return format("%0.16g", v[0].get_double("F")); }
             else if (key == "xi"){ return format("%0.16g", v[0].get_double("xi")); }
             else if (key == "zeta"){ return format("%0.16g", v[0].get_double("zeta")); }
             else if (key == "gammaT"){ return format("%0.16g", v[0].get_double("gammaT")); }