Transition manganese nitrides

Figure 8.9 Structure of MnMoN2 and j3-MnWN2. Examples of ternary transition metal nitrides containing octahedral manganese and trigonal prismatic molybenum/tungsten. Small white = Manganese, Black = Molybenum/Tungsten, Large white = Nitrogen.

The heats of formation of the more common nitrides are shown in Table 9.1. All of the transition metal nitrides are close-packed interstitial structures and in some cases a wide variety of nitrides are formed depending on the number of octahedral holes that are filled. Manganese, for instance, forms... 

These are usually reactions of anhydrous transition and B metal halides with dry alkali metal salts such as the sulphides, nitrides, phosphides, arsenides etc. to give exchange of anions. They tend to be very exothermic with higher valence halides and are frequently initiated by mild warming or grinding. Metathesis is described as a controlled explosion. Mixtures considered in the specific reference above include lithium nitride with tantalum pentachloride, titanium tetrachloride and vanadium tetrachloride, also barium nitride with manganese II iodide, the last reaction photographically illustrated. 

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