Two cobalt oxyfluoride antiferromagnets CoMOF5(pyz)­(H2O)2 (M = Nb 1, Ta 2; pyz = pyrazine) have been synthesized via conventional hydrothermal methods and characterized by thermogravimetric (TGA) analysis, FTIR spectroscopy, electron spin resonance (ESR), magnetic susceptibility, and magnetization measurements at both static low field and pulsed high field. The single-crystal X-ray diffraction indicates both compounds 1 and 2 are isostructural and crystallize in the monoclinic space group C2/m with a two-dimensional Co2+ triangular lattice in the ab plane, separated by the nonmagnetic MOF5 (M = Nb 1, Ta 2) octahedra along the c-axis with large intertriangular-lattice Co···Co distance. Because of low dimensionality together with frustrated triangular lattice, compounds 1 and 2 exhibit no long-range antiferromagnetic order until ∼3.7 K. Moreover, a spin flop transition is observed in the magnetization curves at 2 K for both compounds, which is further confirmed by ESR spectra. In addition, the ESR spectra suggest the presence of a zero-field spin gap in both compounds. The high field magnetization measured at 2 K saturates at ∼7 T with M s = 1.55 μB for 1 and 1.71 μB for 2, respectively, after subtracting the Van Vleck paramagnetic contribution, which is usually observed for Co2+ ions with pseudospin spin of 1/2 at low temperature. Powder-averaged magnetic anisotropy of g = 3.10 for 1 (3.42 for 2) and magnetic superexchange interaction J/k B = −3.2 K for 1 (−3.6 K for 2) are obtained.

The iodate anion group has been widely used for design and synthesis of functional materials including nonlinear optical materials but rarely for magnetic materials. Particularly, none of magnetic iodate fluorides has been reported yet. In this work, first, two novel magnetic iodate fluorides MIO3F (M = Co 1 and Ni 2) have been synthesized by a hydrothermal method and characterized by magnetic susceptibility, magnetization, and heat capacity measurements as well as thermogravimetry, Fourier transform infrared spectroscopy (FT-IR), and ultraviolet–visible–near-infrared (UV–vis–NIR) spectroscopy. Compounds 1 and 2 are isostructural and crystallize in the monoclinic space group P21/n with alternating M2+–F2–M2+–O2–M2+ zigzag spin chains along the b axis, which are further separated by triangular IO3 groups in the ab plane. Magnetic susceptibilities suggest that 1 exhibits an antiferromagnetic long-range order (LRO) at 16.5 K, confirmed by heat capacity results with released entropy consistent with the theoretical value for a pseudo-spin of 1/2 for Co2+ at low temperatures. Meanwhile, 2 displays a broad maximum around 10.5 K for low dimensional magnetism followed by a sharp peak at 5.7 K indicating the occurrence of an LRO transition, in good agreement with the heat capacity measurement. Field-dependent magnetizations show an obvious spin-flop transition around 4.5 T and a magnetic hysteresis loop between 4.5 and 7 T for 1, but only a slight slope change could be observed around 2.3 T for 2. Thermal stability, FT-IR, and UV–vis–NIR spectroscopy of 1 and 2 are also reported.

] n is successfully synthesized by the hydrothermal reaction method. The compound crystallizes in the monoclinic structure with space group P2 1 /c, in which two inequivalent Co ions, bridged by a μ 2 -O monodentate formic acid ligand group, form one-dimensional skew chains along the b axis. The magnetic susceptibility and specific heat data indicate that the compound undergoes two magnetic phase transitions at T N1 = 5.8 K and T N2 = 6.6 K, respectively. Interestingly, the magnetization curve at 2 K presents a 1/2-like magnetization plateau based on the analysis of Hamiltonian diagonalization.

The coordination number Z of the atom W in scintillator ZnWO4 is analyzed based on the X-ray structural data and Raman scattering experiment results. Z is suggested to be 6 that might be more reasonable than 4. t turns out that the luminescence center in ZnWO4 locates at the configuration of the atomic group WO6, instead of WO4-2. We also present some new Raman lines expected bytheoretical analysis.