Results and discussion Phase formation Formation process of

The Raman bands at <200 cm−1 can be attributed mainly to Ni/Mg–Cl related modes [22]. Due to the limited spectroscopic LDE225 and the poor crystallinity of some samples (x=0.31–0.57) some bands (160–190 cm−1) show strong overlap ( Fig. 8). Nevertheless there is a clear systematic shift of these bands towards lower wavenumbers with increasing Mg2+-content of the solid solutions. According to Eq. (7) the band position (?¯) depends on both the force constant (k), which represents the strength of the Ni/Mg–Cl bond and the reduced mass (µ). Therefore the replacement of nickel by magnesium would shift these bands towards higher wavenumber, due to the decrease of the reduced mass (µ). Lockwood et al. [37] and Anderson et al. [38], however, showed by the spectroscopic investigation of CdCl2-type main group- and transition metal–chlorides, anticodon the wavenumbers of the metal–chloride modes are determined mainly by the force constant (k), i.e. by the strength of the metal–chloride bond.equation(7)?¯=12πckμ