And notice that these two nucleotides bond to one another via the phosphol diaster bond. So we have the phosphorus atom and we also have the two aster bonds shown here. And that's exactly why it's called a phosphodia ester bond. Now, notice that the bonding takes place between the third carbon of one sugar and the fifth carbon of the second sugar. And that's exactly why this is called a three to five bond. So this is our phosphol diester bond.