Single-Crystal Paramagnetic Resonance Studies of V(II), Mn(II), and Ni(II) in CsMgCl3 and the Crystal Structure of CsMgCl3

The single-crystal electron spin resonance spectra of (VII), Mn(II), and Ni(II) are reported in the diamagnetic lattice CsMgCl3 at 298 and 77°K. The structure of the host lattice CsMgCl3 is also reported. The crystal system is hexagonal, space group P63/m mc. The basic structural feature is the linear array of [MgCl6]4− octahedra sharing faces directed along the hexagonal c axis. The crystallographic site symmetry at the Mg2+ ions is D3d. The spin resonance spectra of the doped salts Cs[Mg1−x, Vx]Cl3, Cs[Mg1−x, Mnx]Cl3, and Cs[Mg1−x, Nix]Cl3, where x is small, can be readily explained in terms of the axial field Hamiltonian: H = β[g‖HzSz + g⊥(HxSx + HySy)] + D[Sz2 − 13S(S + 1)] + ASzIz + B(SxIx + SyIy). The principal measured quantities are, respectively: V(II)(77°K), g‖ = 1.9740, g⊥ = 1.9760, D(gauss) = 931, A(gauss) = 82.3, B(gauss) = 79.8; Mn(II)(77°K), g‖ = 2.0016, g⊥ = 2.0015, D(gauss) = 313, A(gauss) = 86.5, B(gauss) = 86.5; Ni(II)(77°K), g‖ = 2.257, g⊥ = 2.241, D(gauss) = 18 980.