Many molecular structures have common substructural components. For example, the large number of substituted benzenes all have a common benzene ring.

The Standard Structure dialog enables you to quickly and easily add these common substructures to the molecule you are editing. The dialog is activated by pressing the Structure Edit dialog's Std Structs button. (See the documentation on the Structure Edit Dialog for more details on the edit dialog and on editing molecular structure in general.)

In this example we will create a new chemical and enter its molecular structure. The chemical is 1-hexyl-4-cyclohexylbenzene.

1. Open a knowledge base document. (Open a "working" document or create a copy of a document (see here) if you are just experimenting with this functionality.)
2. Using the tabs at the top of the document, change to the Chemicals Chapter by clicking the left mouse button on Chemicals tab.
3. Press the Add toolbar button (the large plus sign). Alternatively you can choose the Add New Page command from the Edit menu or use the crtl-a keyboard accelerator. A new, blank Chemical page will be added to the current document.
4. Click the left mouse button on the Identifier Pane's edit control and enter the chemical's name: 1-hexyl-4-cyclohexylbenzene. (See documentation on Knowledge Base Documents for details on the layout of Cranium and Synapse documents.)
5. Scroll the data pane down to the Chemical Structure section. Click click the left mouse button in the section's Structure field. The application will activate the Structure Edit dialog.
6. Press the Std Structs button to activate the Standard Structures dialog. Select Straight Chains as the Category and then six (6) as the Chain Size.

   1	Category: lists the categories of standard structures. As each category is selected, other options in the dialog are enabled or disabled.
   2	Chain Size: select the number of carbon atoms to be included in the added structure.

7. Finally press the OK button to add the standard structure to the edit pane.
8. Drag the selected atoms toward the center of the edit pane.
9. Once again, press the Std Structs button to activate the Standard Structures dialog. Select Rings as the Category. Select cyclohexane from the Ring Choices list. Finally, press the OK button.

   1	Category: lists the categories of standard structures. As each category is selected, other options in the dialog are enabled or disabled.
   2	Ring Choices: lists several standard ring structures.

10. The dialog will add the cyclohexane structure to the edit pane. Drag the selected cyclohexane atoms to the right of the previously entered hydrocarbon chain and bond the chain and the ring together with a single bond. (See the documentation on the Structure Edit Dialog for more details on editing molecular structure.)
11. Once again, press the Std Structs button to activate the Standard Structures dialog. Select Rings as the Category. Select benzene from the Ring Choices list. Finally, press the OK button.
12. Move the added benzene ring to the upper right of the cyclohexane ring and join the two rings together, at the 4 position on the cyclohexane ring, with a single bond.
13. Finally, press the dialog's Save button. The structure will be stored in the current document.

Topic	Description
Estimating Chemical Properties	a short video demonstrating how to estimate the physical properties of chemicals using either Synapse or Cranium.
Getting Started using Cranium	provides a quick tour of Cranium's capabilities including a discussion of structure editing.
Getting Started using Synapse	provides a quick tour of Synapse's capabilities including examples of chemical product design.
Chemical Structure Dialog	enables you to create and edit the molecular structure of chemicals and groups.
Chemicals Chapter	the chemicals chapter contains numerous sections for entering and displaying data and estimates including the chemical structure section.