diff --git a/ImageD11/sym_u.py b/ImageD11/sym_u.py
index bfc0371d..44c1f35c 100644
--- a/ImageD11/sym_u.py
+++ b/ImageD11/sym_u.py
@@ -203,6 +203,8 @@ def rhombohedralP():
     """ R3 primitive """
     return generate_group("z,x,y", "-z,-y,-x")
 
+trigonalP = rhombohedralP
+
 def tetragonal():
     """ P4 75"""
     return generate_group ( "-y,x,z", "-x,y,-z" )