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

• A 2D piperazinium cobalt–zinc phosphate has been synthesized and characterized.
• Crystal structure of 1D metastable phase was also determined.
• Thermal behavior of 2D compound is strongly dependent on the selected heating rate.
• Magnetic measurements show no magnetic ordering down to 4 K.

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.

Hydrothermal synthesis and structural characterization of a two-dimensional piperazinium cobalt–zinc phosphate, (C4N2H12)1.5(Co0.6Zn0.4)2(HPO4)2(PO4)·H2O (2D), have been reported. The crystal structure of a one-dimensional piperazinium cobalt–zinc phosphate, (C4N2H12)Co0.3Zn0.7(HPO4)2·H2O (1D) a metastable phase during the hydrothermal synthesis, was also determined. The thermal behavior of 2D compound is strongly dependent on the selected heating rate and the magnetic susceptibility and magnetization measurements show no magnetic ordering down to 4 K. Figure optionsDownload as PowerPoint slide