Regular BiPO4 nanorods, for the first time, and BiOCl lamellae have been successfully synthesized via a facile sonochemical method in a surfactant/ligand-free system under ambient air. The as-prepared products are characterized by XRD, TEM, SAED, FE-SEM, HRTEM, and Raman spectroscopy. The effects of pH and ultrasound irradiation on the phase and morphology of the products are studied and the sonochemical formation mechanisms of 1D and 2D structures are discussed. TEM data from samples made after different reaction times suggest an ultrasound-induced nucleation and an oriented-attachment growth mechanism.

Lead tungstate single crystals with dendritic, flowery and star-like structures have been prepared via a facile, ethylene glycol (EG)-assisted sonochemical method. The concentrations of EG and ultrasound irradiation were found to play crucial roles in the morphology control of the final products. The growth process was investigated by carefully following time-dependent experiments, and the oriented attachment process accompanying Ostwald ripening was proposed for the possible formation mechanism. The optical properties, such as the Raman spectra and photoluminescence (PL) spectra, of the obtained PbWO(4) crystals were studied.

We herein report novel hollow SAPO-34 cubes with a hierarchical internal structure. They are prepared from dry gels containing gelatin by a vapor-phase transport method. Microscopic characterization reveals that the cubes are constructed by symmetrically packed four two-top-point truncated octahedrons encapsulated by dense crystalline shells, exhibiting a structure-in-structure formation. The cubes show either +-shaped or the butterfly like X-shaped black spots on their faces under light. Investigation of the formation process of the hollow SAPO-34 cubes demonstrates a surface to core crystal growth route, which has not been found in vapor-phase transport synthesis of zeolites. A possible formation mechanism is proposed.

Mechanism. -Regular BiPO4 nanorods and BiOCl lamellae are easily synthesized from Ni(NO3)3 and Na3PO4 by a sonochemical method in a surfactant/ligand-free system under ambient air. The effects of pH and ultrasound irradiation on the phase and morphology of the products are studied and the sonochemical formation mechanisms of one-and two-dimensional structures are discussed. An ultrasound-induced nucleation and an oriented-attachment growth mechanism are proposed. -(GENG, J.; HOU, W.-H.; LV, Y.-N.; ZHU*, J.-J.; CHEN, H.-Y.; Inorg.

The structural, dielectric and piezoelectric properties of (1-x)(Bi 1/2 Na 1/2 ) TiO 3 -xBaTiO 3 ceramics were investigated for the compositional range, x=0.02, 0.04, 0.06, 0.08, 0.10. The samples were synthesized by a conventional solid-state reaction technique. All compositions show a single perovskite structure, and X-ray powder diffraction patterns can be indexed using a rhombohedral structure. Lattice constants and lattice distortion increase while the amount of BaTiO 3 increases. The X-ray diffraction results show the morphotropic phase boundary (MPB) of (1-x)(Bi 1/2 Na 1/2 ) TiO 3 -xBaTiO 3 exists in near x=0.06-0.08. Temperature dependence of dielectric constant ε T 33 /ε 0 measurement reveals that all compositions experience one structural phase and two ferroelectric phases transition below 400 o C: rhombohedral (or rhombohedral plus tetragonal) ferroelectric phase tetragonal antiferroelectric phase tetragonal paraelectric phase. Relaxor behaviors exist in the course of ferroelectric to antiferroelectric phase transition. Dielectric and piezoelectric properties are enhanced in the MPB range for (1-x)(Bi 1/2 Na 1/2 )TiO 3 -xBaTiO 3 .