Published online by Cambridge University Press: 23 September 2016
Protoplanetary disks are now intensively observed by mm arrays. While resolved images of CO rotation lines permit a better understanding of their physical structure, molecular surveys provided by current mm telescopes are currently sensitivity limited and do not allow a quantitative analysis of the chemical properties of disks. In this paper, I review the actual observational knowledge of the chemistry in the outer disks surrounding low and intermediate PMS stars and traced by mm data.