diff --git a/Cantera/src/thermo/electrolytes.h b/Cantera/src/thermo/electrolytes.h
new file mode 100644
index 000000000..eecd6f878
--- /dev/null
+++ b/Cantera/src/thermo/electrolytes.h
@@ -0,0 +1,54 @@
+/**
+ *  @file electrolytes.h
+ *
+ * Header file for a common definitions used in electrolytes
+ * thermodynamics.
+ */
+/*
+ * Copywrite (2006) Sandia Corporation. Under the terms of 
+ * Contract DE-AC04-94AL85000 with Sandia Corporation, the
+ * U.S. Government retains certain rights in this software.
+ */
+/*
+ *  $Id$
+ */
+#ifndef CT_ELECTROLYTES_H
+#define CT_ELECTROLYTES_H
+namespace Cantera {
+  /**
+   * Electrolyte species type
+   */
+  const int cEST_solvent  = 0;             // Solvent species (neutral)
+  const int cEST_chargedSpecies = 1;       // Charged species (charged)
+  const int cEST_weakAcidAssociated = 2;   // Species which can break
+                                           // apart into charged species.
+                                           // It may or may not be charged.
+                                           // These may or may not be
+                                           // be included in the
+                                           // species solution vector.
+  const int cEST_strongAcidAssociated = 3; // Species which always breaks
+                                           // apart into charged species.
+                                           // It may or may not be charged.
+                                           // Normally, these aren't included
+                                           // in the speciation vector.
+  const int cEST_polarNeutral = 4;         // Polar neutral species
+  const int cEST_nonpolarNeutral = 5;      // Nonpolar neutral species. These
+                                           // usually have activity coefficnt
+                                           // corrections applied to them to
+                                           // account for salting-out effects
+
+  /**
+   *  eosTypes returned for this ThermoPhase Object
+   */
+  const int cHMWSoln0 = 45010;
+  const int cHMWSoln1 = 45011;
+  const int cHMWSoln2 = 45012;
+
+  /**
+   *  eosTypes returned for this ThermoPhase Object
+   */
+  const int cDebyeHuckel0 = 46010;
+  const int cDebyeHuckel1 = 46011;
+  const int cDebyeHuckel2 = 46012;
+}
+#endif