Structure searching in CAS Online using STN Express:
An introductory workshop

Building structures

1. Launch STN Express
2. Choose Query from menu bar at top
   1. Choose Prepare Structure Query
   2. Choose New to create a new structure
   3. Choose Open to modify an existing structure
3. The structure drawing part of STN Express will appear and consists of 4 main parts
   1. Blank screen
   2. Tool Palette
   3. Common Atoms and Bonds Palettes
   4. Pull-Down Menus

Tool palette

Tool	Function
Pencil	Draw atoms/bonds using current atom/bond
Rxn	Enable reaction drawing tools
Ring	Draw 3- to 15- member ring systems
Chain	Draw 1- to 30- member chains
Eraser	Delete objects
Rectangle	Select (highlight) objects
Lasso	Select (grab) objects
A	Add text to screen (not searched)
?	Help for this Palette

Common atoms and bonds palettes:

• Click once for single use
• Click twice in rapid succession for multiple use
• Current atom or bond is shown in thick-line bordered boxes
• Click box on far right to return to default values (carbon/single bond)