SO2-4 ions direct the one-dimensional growth of 5Mg(OH)2 • MgSO4 • 2H2O

One-dimensional (1D) 5Mg(OH)(2) center dot MgSO4 center dot 2H(2)O (512MHSH) materials directed by SO42- ions in aqueous solution were synthesized on a large scale. Our designed experiments show that the concentration of SO42- ions, pH and temperature allow us to explain quite well the growth dynamics. The ideal morphology of 512MHSH crystals was predicted from the chemical bond viewpoint. Crystallographically, SO42- ions aligned along the b-axis of 512MHSH crystals play a bridge role to link two adjacent Mg(OH)(6)(4-) fragments, and thus direct 512MHSH to preferentially form 1D structures. Both theoretical and experimental results showed that SO42- ions directed the 1D growth of 512MHSH during the transformation from irregular Mg(OH)2 particles to 1D 512MHSH structures. The current work greatly extends practical applications of Mg(OH)2 due to low agglomeration. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.