diff --git a/src/REAX/pair_reax.cpp b/src/REAX/pair_reax.cpp
index a51737589f..61aeaaa5c3 100644
--- a/src/REAX/pair_reax.cpp
+++ b/src/REAX/pair_reax.cpp
@@ -525,10 +525,13 @@ void PairREAX::coeff(int narg, char **arg)
 
   // read args that map atom types to elements in potential file
   // map[i] = which element the Ith atom type is, -1 if NULL
+  // NOTE: for now throw an error if NULL is used to disallow use with hybrid
+  //       qEq atrix solver needs to be modified to exclude atoms
 
   for (int i = 3; i < narg; i++) {
     if (strcmp(arg[i],"NULL") == 0) {
       map[i-2] = -1;
+      error->all("Cannot currently use pair reax with pair hybrid");
       continue;
     }
     map[i-2] = force->inumeric(arg[i]);
diff --git a/src/USER-REAXC/pair_reax_c.cpp b/src/USER-REAXC/pair_reax_c.cpp
index 23b831b6f4..4a328a7b18 100644
--- a/src/USER-REAXC/pair_reax_c.cpp
+++ b/src/USER-REAXC/pair_reax_c.cpp
@@ -223,12 +223,15 @@ void PairReaxC::coeff( int nargs, char **args )
  
   // read args that map atom types to elements in potential file
   // map[i] = which element the Ith atom type is, -1 if NULL
+  // NOTE: for now throw an error if NULL is used to disallow use with hybrid
+  //       REAX/C lib will have to be modified to allow this
 
   int itmp;
   int nreax_types = system->reax_param.num_atom_types;
   for (int i = 3; i < nargs; i++) {
     if (strcmp(args[i],"NULL") == 0) {
       map[i-2] = -1;
+      error->all("Cannot currently use pair reax/c with pair hybrid");
       continue;
     }