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The mild preparation of submicron Cu 2 O and CuO crystallites from a solid metallorganic molecular precursor (copper acetylacetonate, Cu-(ACAC) 2 ) has been achieved via two simple steps: firstly, the Cu-(ACAC) 2 precursor was precipitated from the reaction of copper acetate and acetyl acetone in distilled water under the ambient condition; then, cubic phase Cu 2 O submicrocrystals with the size of mostly 80–260 nm could be produced by hydrothermal treatment of the Cu-(ACAC) 2 in distilled water at 180 °C for 12 h, while monoclinic structure CuO submicrocrystals with the size of about 130–470 nm could be obtained by thermolysis of the Cu-(ACAC) 2 in air at 300 °C for 5 h. The as-synthesized products were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electronic microscopy (SEM).

Uniform, submicron BaTiO 3 crystallites in tetragonal structure were synthesized by a novel low-temperature liquid–solid reaction method mainly via two simple steps: firstly, BaO 2 ·H 2 O 2 submicron particles of about 130–450 nm were precipitated from the reaction of BaCl 2 and H 2 O 2 in a slightly alkaline (pH 8) aqueous solution under the ambient condition; secondly, tetragonal phase BaTiO 3 submicrocrystals with the size in the range of 180 to 400 nm could be produced by subjecting the as-prepared BaO 2 ·H 2 O 2 and commercial TiO 2 submicron particles to thermal treatment in air at 700 °C for 10 h. The as-obtained products were characterized by X-ray powder diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and inductively coupled plasma-atomic emission spectroscopy, and scanning electron microscopy.

The low-temperature solid-phase synthesis of high-purity CdTiO 3 submicrocrystals has been achieved via two simple steps: firstly, CdO 2 nanoparticles with the size of about 5 nm were precipitated from the reaction of 3CdSO 4 ·8H 2 O and H 2 O 2 in an alkalescent aqueous solution (pH=8.0) under the ambient condition; secondly, ilmenite-phase CdTiO 3 powders with the sizes in the range of 150–350 nm could be produced by subjecting the as-prepared CdO 2 nanoparticles and TiO 2 powders to thermal treatment in air at 600 °C for 6 h. The as-obtained products were characterized by means of powder X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM).

The phase-controlled synthesis of ZnS nanocrystallites from an air-stable single-source molecular precursor (zinc diethyldithiocarbamate: Zn-(DDTC)2) has been achieved by two facile steps: firstly, the Zn-(DDTC)2 was prepared directly via the precipitation reaction of zinc acetate and sodium diethyldithiocarbamate in distilled water under ambient condition; secondly, pure cubic and hexagonal phases of ZnS nanocrystallites could be obtained just by low-temperature (150–200 °C) solvothermal decomposition of the Zn-(DDTC)2 in distilled water and ethanol, respectively. The as-obtained products were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and UV–vis absorption spectra.

Without the use of any extra surfactant or template, γ-MnOOH single crystalline nanowires were synthesized directly through the hydrothermal reaction between KMnO 4 and toluene in distilled water at 180 °C for 24 h; and β-MnO 2 single crystalline nanowires could be obtained just by calcination of the γ-MnOOH nanowires in air at 280 °C for 5 h. The as-prepared γ-MnOOH and β-MnO 2 nanowires were characterized by X-ray powder diffraction, atomic absorption spectroscopy, Fourier transformed infrared spectroscopy, scanning electron microscope, transmission electron microscope, high-resolution transmission electron microscope and selected area electron diffraction.

Pure hexagonal phase of ZnO nanocrystallites with the sizes of several nanometers were synthesized by low-temperature (180 °C) thermal decomposition in air of a “green” single-source inorganic precursor, ZnO 2 nanocrystallites, which were derived from the hydrothermal reaction of Zn(Ac) 2 and H 2 O 2 in an alkaline aqueous solution (pH=10.0) at 100 °C for 12 h, and characterized by powder X-ray diffraction (XRD), transmission electronic microscopy (TEM), UV–Vis absorption spectrum, and room temperature photoluminescence (RTPL) spectrum. The use of ZnO 2 nanocrystallites as the precursor to ZnO has some advantages: easy preparation, low decomposition temperature, no unwanted by-products and free of pollution to both the target products and the environment upon thermal decomposition (ZnO 2 =ZnO+ 1 2 O 2 ).

The shape-controlled synthesis of PbS microcrystallites from an air-stable single-source molecular precursor (lead diethyldithiocarbamate: Pb-DDTC) under mild conditions has been achieved by two simple steps: firstly, the Pb-DDTC was prepared directly through the precipitation reaction of lead acetate and sodium diethyldithiocarbamate in distilled water at room temperature; secondly, without the use of any extra surfactant/template, pure PbS microcrystallites with irregular polyhedral, cubic, and fish bone-, star-, and flower-like morphologies could be obtained just via solvothermal decomposition of the Pb-DDTC in three different solvents (including ethanol, ethylene glycol and ethylenediamine) at 150–180 °C for 12 h. The as-obtained PbS microcrystallites were characterized by means of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

A simple and completely green hydrothermal route has been developed to synthesize copper (Cu) nanocrystallites based on the reduction of CuO by α-D-glucose in distilled water at 180 °C for 24 h. X-ray diffraction, energy dispersive X-ray spectrum and X-ray photoelectron spectroscopy analysis revealed that the as-synthesized product is of pure Cu with face centered cubic structure. Transmission electron microscopy image indicated that the obtained Cu powders consist of uniform, spherical nanocrystallites with the diameters ranging from 320 to 550 nm. Also, the effects of the reaction temperature and reaction time on the phase(s) of the resultant products were investigated, and the possible formation mechanism of Cu in this hydrothermal system was discussed.

Nanocrystalline CuS powders with spherical, quadrate, plate-like and tubular morphologies have been synthesized via hydrothermal treatment of Na 2 S 2 O 3 ·5H 2 O and different copper sources (including CuO, CuSO 4 ·5H 2 O and CuCl 2 ·2H 2 O) in water at 130–170°C for 6–24 h. The morphology and size of the obtained products can be well controlled simply by adjusting the copper sources, reaction temperature and reaction time. The possible formation mechanisms of nanocrystalline CuS powders from different copper sources and Na 2 S 2 O 3 ·5H 2 O during the hydrothermal processing were also proposed.

Phase-pure metastable γ-MnS (wurtzite structure) crystallites were synthesized for the first time by a mild hydrothermal method based on the reactions between manganese acetate (Mn(CH3COO)2) and thioacetamide in aqueous solution at 60–130°C for 20 h. The as-prepared γ-MnS crystallites have been characterized by X-ray diffraction, scanning electron microscopy (SEM), optical absorption spectra. The SEM images showed that the obtained γ-MnS powders were well crystallized even when the processing temperature was as low as 60°C. The optical band gap of the obtained γ-MnS crystallites was estimated to 3.8 eV.