diff --git a/interfaces/cython/cantera/ctml_writer.py b/interfaces/cython/cantera/ctml_writer.py
index 306afeccd..85ac2bee9 100644
--- a/interfaces/cython/cantera/ctml_writer.py
+++ b/interfaces/cython/cantera/ctml_writer.py
@@ -2294,47 +2294,6 @@ class RedlichKwongMFTP(phase):
             k['model'] = self._kin
 
 
-class redlich_kwong(phase):
-    """A fluid with a complete liquid/vapor equation of state.
-    This entry type selects one of a set of predefined fluids with
-    built-in liquid/vapor equations of state. The substance_flag
-    parameter selects the fluid. See purefluids.py for the usage
-    of this entry type."""
-
-    def __init__(self,
-                 name = '',
-                 elements = '',
-                 species = '',
-                 note = '',
-                 substance_flag = 7,
-                 initial_state = None,
-                 Tcrit = 1.0,
-                 Pcrit = 1.0,
-                 options = []):
-
-        phase.__init__(self, name, 3, elements, species, note, 'none',
-                       initial_state, options)
-        self._subflag = 7
-        self._pure = 1
-        self._tc = 1
-        self._pc = 1
-
-    def conc_dim(self):
-        return (0,0)
-
-    def build(self, p):
-        ph = phase.build(self, p)
-        e = ph.child("thermo")
-        e['model'] = 'PureFluid'
-        e['fluid_type'] = repr(self._subflag)
-        addFloat(e, 'Tc', self._tc, defunits = "K")
-        addFloat(e, 'Pc', self._pc, defunits = "Pa")
-        addFloat(e, 'MolWt', self._mw, defunits = _umass+"/"+_umol)
-        ph.addChild("kinetics")
-        k['model'] = 'none'
-
-
-
 class ideal_interface(phase):
     """A chemically-reacting ideal surface solution of multiple species."""
     def __init__(self,
diff --git a/src/tpx/RedlichKwong.h b/src/tpx/RedlichKwong.h
index 8ee1940a5..92d36bc7b 100644
--- a/src/tpx/RedlichKwong.h
+++ b/src/tpx/RedlichKwong.h
@@ -3,18 +3,22 @@
 #define TPX_RK_H
 
 #include "cantera/tpx/Sub.h"
+#include "cantera/base/global.h"
 #include <math.h>
 
 namespace tpx
 {
 const double GasConstant = 8314.3;
 
+//! @deprecated To be removed after Cantera 2.3.
 class RedlichKwong : public Substance
 {
 
 public:
 
     RedlichKwong() {
+        Cantera::warn_deprecated("class RedlichKwong",
+                                 "To be removed after Cantera 2.3.");
         setParameters(1.0, 1.0, 1.0);
         m_name = "Redlich-Kwong";
         m_formula = "-";
diff --git a/src/tpx/lk.h b/src/tpx/lk.h
index b8690e0fd..55c554c6d 100644
--- a/src/tpx/lk.h
+++ b/src/tpx/lk.h
@@ -3,16 +3,20 @@
 #define TPX_LK_H
 
 #include "cantera/tpx/Sub.h"
+#include "cantera/base/global.h"
 
 namespace tpx
 {
 
+//! @deprecated To be removed after Cantera 2.3.
 class leekesler : public Substance
 {
 public:
     leekesler(double tc = 1.0, double pc = 1.0,
               double wt = 1.0, int itype = 0) {
         Tcr = tc;
+        Cantera::warn_deprecated("class leekesler",
+                                 "To be removed after Cantera 2.3.");
         Pcr = pc;
         Mw = wt;
         Isr = itype; // simple fluid or reference