Step Jmol script Result In this case, we needed to construct the operator PRP -1 , rather than P -1 RP, since the point we will be operating upon is described by the initial group, not the target group. That said, we could have gone the other way using Jmol's method of going from subgroup supergroup. P = matrix("P2/c >super>P2/m") R = symop("-x,y,-z+1/2") R2= !P*R*P print R2.format("a,b,c") Suffice it to say, all this would be very difficult without a well-defined scriptable notation for settings and group-subgroup transformations.