A series of
![](/i<font color=)
mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-NiS three-dimensional (3D) flowerlike architectures with an average diameter of 2-4
![](/i<font color=)
mages/entities/mgr.gif">m have beenhydrother
mally synthesized in the presence of ammonia and trisodium citrate. Morphology modification can be conveniently realizedby varying the reaction temperature. At 120
![](/i<font color=)
mages/entities/deg.gif">C the flowerlike architectures were composed of nanoneedles. At 180
![](/i<font color=)
mages/entities/deg.gif">C the flowerlikearchitectures were composed of nanorods, while mixtures of nanoneedle-based and nanorod-based flowerlike architectures wereobtained in the temperature range of 140-160
![](/i<font color=)
mages/entities/deg.gif">C. Citrate anion was introduced as both a coordinating reagent and a shape modifierto control the anisotropic growth of
![](/i<font color=)
mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-NiS. Besides a probable growth mechanism, the citrate-assisted Ostwald ripening process wasproposed to explain the for
mation of flowerlike architectures on the basis of transmission electron microscopy observations. Sucha simple and mild synthetic route
may be extended to fabricate complex 3D architectures of other
materials.