Answer: Ionic Bonds
"When it forms the nitride ion, it gains three electrons to form a 3- ion: N3− . In ionic compounds, the charges of constituent ions must balance. This can be achieved by having three sodium ions per nitride ion. Therefore, the formula of sodium nitride is Na3N"
Explanation:
https://socratic.org/questions/what-is-the-formula-for-sodium-nitride#:~:text=When%20it%20forms%20the%20nitride,nitride%20is%20Na3N%20.
