Binding of nitrogen by base metals

Principle

In this experiment the reactivity of nitrogen with various metals is investigated. Nitrogen as a typical non-metal should react with metals to the corresponding salt in the form of an exothermic reaction. However metals react only very little with nitrogen. Nitrogen reacts at room temperature only a little amount of metals (alkali metals such as lithium) to the corresponding nitrides. This reason is that (elementary) nitrogen  exists as a molecule and the nitrogen atoms are connected by three binding electron pairs. The triple bond between both nitrogen atoms is extremely unreactive. However, it is possible that nitrogen reacts with reactive metals (e.g., calcium or magnesium), which is shown in this experiment.

Learning objectives

• reaction behaviour of nitrogen
• preparation of metal nitrids