In the Chem-Ray element.tbl file each element is given a van der waals radius. When drawings are made in the ball and stick format, this van der Waals radius for each element is multiplied by the atom radius factor. Values of about .18-.25 are normal values. The atom radius command allows one to change this value. A small value will give a skinny bond, a large value will give a fat bond.
Strange things can happen if the bond radius is made larger than the atom radii.
The program will draw a bond between two atoms if the distance between them is less than the sum of their covalent bonding radii. Note that the element symbols are case sensitive. Xx program will respond with the current bond radius for element Xx cr Xx n specifies that the bond radius for element Xx will be n Angstroms. Exit The Exit command closes all windows and exits the program. This is an absolute command.