Longjiang Zou

CRYSTALLIZATION BEHAVIOR OF MAGNESIUM SALTS: A SUMMARY OF SOME EXPERIMENTAL OBSERVATIONS

Some efficient methods have been developed to chemically prepare some magnesium salt products with multiscale morphologies such as MgCO3·3H2O and 5Mg(OH)2·MgSO4·2H2O whiskers, Mg5(CO3)4(OH)2·4H2O microplates and aggregates, and Mg(OH)2 plates and spheres. The crystallization processes of the as-prepared products were studied by designing different reaction routes and corresponding growth morphologies. In these solution chemical systems, Mg2+ cation was found to be easily coordinated by various ligands, and can be easily transformed into various compounds with variable compositions. The current crystallization observations of some magnesium salts can be readily simulated by the chemical bonding theory of single crystal growth. These results can guide the further studies of various magnesium salts with controllable morphologies.

CHEMICAL PREPARATION OF MgO WHISKERS

A useful method is described for the chemical synthesis of high length-radius ratio magnesium oxide (MgO) whiskers at ambient temperature. The diameter of MgO whiskers falls in the range of 2–5 μm with a length of 30–50 μm. The length-radius ratio generally falls in the range of 10–30. Energy-dispersive X-ray spectrometer analysis reveals that the whiskers are composed of Mg and O elements. Microscopic morphologies and structures are well studied by scanning electron microscopy and X-ray diffraction. The growth mechanism of MgO whiskers is also proposed on the basis of crystallographic characteristics.