diff --git a/src/main/org/openscience/cdk/interfaces/IBond.java b/src/main/org/openscience/cdk/interfaces/IBond.java
index 2f6f7b7360e..a542b1ad6d0 100644
--- a/src/main/org/openscience/cdk/interfaces/IBond.java
+++ b/src/main/org/openscience/cdk/interfaces/IBond.java
@@ -49,21 +49,29 @@ public enum Order {
}
/**
- * Enumeration of possible stereo types of bonds.
+ * Enumeration of possible stereo types of two-atom bonds. The
+ * Stereo type defines not just define the stereochemistry, but also the
+ * which atom is the stereo center for which the Stereo is defined.
+ * The first atom in the IBond (index = 0) is the start atom, while
+ * the second atom (index = 1) is the end atom.
*/
public enum Stereo {
- /** A bonds for which there is no stereochemistry. */
+ /** A bond for which there is no stereochemistry. */
NONE,
- /** A bonds pointing up of which end is above the drawing plane. */
+ /** A bond pointing up of which the start atom is the stereocenter and
+ * the end atom is above the drawing plane. */
UP,
- /** A bonds pointing up of which start is above the drawing plane. */
+ /** A bond pointing up of which the end atom is the stereocenter and
+ * the start atom is above the drawing plane. */
UP_INVERTED,
- /** A bonds pointing down of which start is above the drawing plane. */
+ /** A bond pointing down of which the start atom is the stereocenter
+ * and the end atom is below the drawing plane. */
DOWN,
- /** A bonds pointing down of which end is above the drawing plane. */
+ /** A bond pointing down of which the end atom is the stereocenter and
+ * the start atom is below the drawing plane. */
DOWN_INVERTED,
- /** A bond for which there is stereochemistry, we just don't know
- * which one.
+ /** A bond for which there is stereochemistry, we just do not know
+ * if it is UP or DOWN. The start atom is the stereocenter.
*/
UP_OR_DOWN,
/** Indication that this double bond has a fixed, but unknown E/Z