Dr. Heinz Jürgen Beister, Dipl.-Ing. (FH) Sabine Haag, Prof. Dr. Rüdiger Kniep, Dr. Klaus Strössner and Priv.-Doz. Dr. Karl Syassen
The transformation of α-Li3N to β-Li3N occurs at 600 MPa and room temperature. The reverse transformation, however, only begins to take place above 200°C under normal pressure. β-Li3N crystallizes as the Na3As structure type. This modification allows Li3N to be placed systematically in the structural series of alkali-metal compounds A3B involving elements of the nitrogen group (A = Li, Na, K, Rb, Cs; B = N, P, As, Sb, Bi). Since the phase transition occurs at relatively low pressure, the formation of small amounts of β-Li3N upon grinding with a mortar and pestle cannot be ruled out. Indeed, X-ray powder diffractions of α-Li3N always reveal the presence of small amounts of β-Li3N.