The number of $\text{P}-\text{O}-\text{P}$ bridges in the structure of phosphorus pentoxide and phosphorus trioxide are respectively:

1. Phosphorus trioxide (${\text{P}}_4{\text{O}}_6$): Has a cage-like structure where each of the 6 edges of the ${\text{P}}_4$ tetrahedron contains an Oxygen bridge. Total $\text{P}-\text{O}-\text{P}$ bridges = 6.2. Phosphorus pentoxide (${\text{P}}_4{\text{O}}_{10}$): Also has the same 6 bridge oxygen atoms. The additional 4 oxygen atoms are terminal (double bonded to P). Total $\text{P}-\text{O}-\text{P}$ bridges = 6.Both structures have 6 $\text{P}-\text{O}-\text{P}$ linkages.