Many estimation techniques require knowledge of a chemical's molecular structure. Some techniques require only information about the chemical's family, e.g., is the chemical chlorinated. Other techniques, e.g., group contribution techniques, require a chemical's structure to be completely dissected into molecular fragments.
Cranium and Synapse use a simple connectivity model to represent molecular structure. Atoms and bonds are connected into a simple graph.
The tool buttons on the dialog's left are used to change drawing modes. The controls at the dialog’s top are used to specify the current element and the current bond type. The large central window is the canvas on which you draw your structure.
|Selection Tool: Click on an atom to select it or click and drag the mouse to select several atoms.
|Eraser Tool: click on atoms or bonds to remove them from the current structure.
|Atom Tool: click anywhere in the edit plane to create a new atom using the current element. (You cannot place a new atom on top of an existing atom.)
|Bond Tool: click on pairs of atoms to connect them with the current bond type.
|Grid Option: press this tool button to have atoms aligned to the grid when created or moved.
|Auto-bond Option: press this tool button to have a new atom automatically bonded to the previously created atom.
|Subtractable Option: press this tool button to have new atoms be non-subtractable atoms.
Group molecular structures are edited in a similar manner as chemical molecular structures. The key difference is that a group structure can include special elements, non-subtractable atoms and ring bonds. For example:
See documentation on the Structure Edit Dialog for further details on editing molecular structures.
|Estimating Chemical Properties
|a short video demonstrating how to estimate the physical properties of pure chemical using either Synapse or Cranium.
|Estimating Mixture Properties
|a short video demonstrating how to estimate the physical properties of mixtures using either Synapse or Cranium.
|Getting Started using Cranium
|provides a quick tour of Cranium's capabilities including physical property estimation and a discussion of structure editing.
|Getting Started using Synapse
|provides a quick tour of Synapse's capabilities including examples of chemical product design.