Answer;
-ADP 
When ATP loses a phosphate, energy is released and ADP is formed
Step-by-step explanation;
 In a process called cellular respiration, chemical energy in food is converted into chemical energy that the cell can use, and stores it in molecules of ATP. 
The most common is a molecule that we call ATP (Adenosine triphosphate). ATP is a nucleic acid containing three high energy phosphate groups. It breaks off these groups to release measured amounts of energy.
 When ATP loses one phosphate group, it becomes Adenosine diphosphate (ADP).