There are \(24 ( = 4!\) this being the number of permutations of \(4\) ligands  among \(4\) sites) ways of writing the projection formula ; \(12 \) correspond to one  enantiomer and \(12 \) to the other. , Twelve of these, corresponding to the \((+)\) enanti_omer, are depicted in Fig. ; the \(12\) mirror images of those shown would  represent the \((-)\) isomer.