The chemical bond that joins the sugar of one nucleotide to the phosphate group of the next nucleotide is a phosphodiester bond.

Here's a breakdown:

* Phosphate group: The phosphate group is attached to the 5' carbon of the sugar molecule in one nucleotide.

* Sugar: The sugar (usually deoxyribose in DNA or ribose in RNA) is the central component of a nucleotide.

* Bond formation: The phosphate group from one nucleotide reacts with the hydroxyl group (OH) on the 3' carbon of the sugar in the next nucleotide. This reaction removes a water molecule (H2O) and forms a phosphodiester bond, connecting the two nucleotides.

This process repeats, forming a long chain of nucleotides linked by phosphodiester bonds, creating the backbone of DNA or RNA.