Defining enantiomer of morphine by R/S designation

How to know if the following chemical structure of morphine is an R or S? What I basically need to know is: which chirality center do we use to make the decision?


$\hskip2in$![enter image description here](https://i.stack.imgur.com/7dWojt.png)




The structure that you are showing is neither R nor S.


As it has five chirality centers you need to look at all of them.


$\hskip3in$![enter image description here](https://i.stack.imgur.com/cF8ib.png)


You can see in the above figure that there are three R and two S centers in the configuration of morphine that you posted.


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