Macro Csixring[9]

This macro typesets a carbon sixring as a regular hexagon. A benzene ring can be drawn with alternating double bonds or with a circle inside the ring. The ring positions to which R1, R2, R3, R4, R5, and R6 are attached are designated as position 1, 2, 3, 4, 5, and 6, respectively:

$\displaystyle \sixring$$R1$$R2$Q$R4$$R5$$R6$$R7$$R8$D   $\displaystyle \sixring$QQ$R3$QQQSSC

Arguments 1–6:
An argument of ``Q'' causes no action. All other argument values are used as the respective substituent formulas R1, R2, R3, R4, R5, and R6.
Argument 7:
An argument of ``D'' typesets a second bond between ring positions 1 and 2. An argument of ``S'' causes no action. All other argument values are used as the substituent formula R7.
Argument 8:
An argument of ``D'' typesets a second bond between ring positions 3 and 4. An argument of ``S'' causes no action. All other argument values cause an outside double bond to be drawn from ring position 3 and the argument itself to be put at the end of the double bond as substituent formula R8.
Argument 9:
An argument of ``D'' typesets a second bond between ring positions 5 and 6. An argument of ``C'' typesets a circle inside the ring. No action is taken for any other value of the argument.