Hydrothermal synthesis and characterization of a two-dimensional piperazinium cobalt-zinc phosphate via a metastable one-dimensional phase

摘要

A two-dimensional piperazinium cobalt–zinc phosphate, formulated as (C4N2H12)1.5(Co0.6Zn0.4)2(HPO4)2(PO4)·H2O (2D), was synthesized under hydrothermal conditions. The crystal structure was determined using single-crystal X-ray diffraction data (monoclinic P21/c, a=8.1165(3) Å, b=26.2301(10) Å, c=8.3595(4) Å, and β=110.930(5)°) and the hydrogen atom positions were optimized by DFT calculations. A single-crystal corresponding to one-dimensional metastable phase, (C4N2H12)Co0.3Zn0.7(HPO4)2·H2O (1D), was also isolated and the crystal structure was determined (monoclinic P21/c, a=8.9120(6) Å, b=14.0290(1) Å, c=12.2494(5) Å, and β=130.884(6)°). The bulk was characterized by chemical (C–H–N) analysis, powder X-ray diffraction (PXRD), powder X-ray thermodiffractometry (HT-XRD), transmission electron microscopy (STEM(DF)-EDX and EFTEM), and thermal analysis (TG/SDTA-MS), including activation energy data of its thermal decomposition. The magnetic susceptibility and magnetization measurements show no magnetic ordering down to 4 K.