diff --git a/Code/Mantid/docs/source/algorithms/SetSampleMaterial-v1.rst b/Code/Mantid/docs/source/algorithms/SetSampleMaterial-v1.rst
index afdff0403c38566e1da80fc0262fa0b56f0a187b..695a896bbdd40f997d013113d63c919ce7853795 100644
--- a/Code/Mantid/docs/source/algorithms/SetSampleMaterial-v1.rst
+++ b/Code/Mantid/docs/source/algorithms/SetSampleMaterial-v1.rst
@@ -24,9 +24,9 @@ isotopes have been taken from
 
 Chemical Composition with Examples
 ##################################
-- ``H2 O``
-- ``(H2)2 O``
-- ``D2 O``
+- ``H2 O`` - Isotopically averaged Hydrogen
+- ``(H2)2 O`` - Heavy water
+- ``D2 O`` - Another way to specify heavy water
 
 Enter a composition as a molecular formula of elements or isotopes. 
 For example, basic elements might be ``H``, ``Fe`` or ``Si``, etc.