# How do you name the compound Ca_3N_2?

$\text{Calcium nitride}$
As a Group 2 metal, calcium commonly forms a $C {a}^{2 +}$ ion.
Nitrogen, in exceptional cirecumstances, can form a ${N}^{3 -}$ ion.
When $\text{calcium nitride}$ forms (for instance when calcium is heated under dinitrogen), the ionic solid must be electrostatically neutral, i.e. $3 \times C {a}^{2 +} + 2 \times {N}^{3 -}$ combine to give a neutral salt.