# Distinguishing cis and trans positions

What I fail to understand is why does trans isomer contain $$2$$ $$\ce{Cl}$$ at axial positions but $$2$$ $$\ce{NH3}$$ are not taken to be so. Isn't the two $$\ce{NH3}$$ in the trans isomer in the picture cis to each other?

• Trans and cis here are relative terms: the structures shown are with respect to Cl, while it can also be made with respect to NH3 as well – Yusuf Hasan Jan 26 '19 at 8:29
• According to IUPAC nomenclature, in case of octahedral systems, the terms cis and trans are only used for octahedral centres of the form $\ce{[Ma2b4]}$, i.e. with four ligands of one kind and two of another. – Faded Giant Jan 26 '19 at 8:42