Final answer:
The anion in the compound Li3N is called the nitride ion (N3-).
Step-by-step explanation:
For the compound Li3N, the name of the anion is derived from the element nitrogen. By taking the stem of the element name and appending the suffix '-ide', followed by the word 'ion', you get the name for the anion. Therefore, the anion in lithium nitride (Li3N) is known as the nitride ion (N3-).
To provide a few more examples for educational purposes, other monatomic anions include the chloride ion (Cl-), oxide ion (O2-), sulfide ion (S2-), and carbide ion (C4-), derived from the elements chlorine, oxygen, sulfur, and carbon, respectively.