The chemical name of calcium nitride is Ca3N2. It has different isomorphous forms, out of which a-calcium nitride is more commonly found. It can be used to obtain reactive nitride ions, and it is also known as a-calcium hydride (desiccant) [1].
Ionic or Covalent?
Ionic means that the molecule is made up of cations and anions which are other than H+ or OH-. This is a type of ionization process, where the molecule is dissociated into ions – one positive and one negative. The ionic character of a molecule is determined by Fajan’s rule of polarizability: every covalent molecule has some percentage of ionic character or vice versa.
If the ionic character of a molecule decreases, it becomes covalent. If it increases, it becomes non-ionic.
It is important to note that a metal-nonmetal compound is named as if it were ionic, unless the nonmetal has no common oxidation state, in which case it is omitted. For example, N2 is a nitrogen-containing gas that has no common oxidation state.
Hence, the formula of a compound should have the positive content listed first and then the negative content. This is the most important rule for naming ionic compounds.
Synthesis of Ca3N2
Calcium nitride is synthesized from distilled fibrous metallic calcium in a pure nitrogen stream heated at 450 deg C. The nitridation of calcium metal to calcium nitride occurs very rapidly in this temperature range, with crystalline transformation occurring in 3 to 4 hours. It is a fast and efficient synthesis method for obtaining calcium nitride, which can be further purified to the highest purity by annealing at 400 deg C.