Abstract: <FONT face=Verdana>Hexagonal close-packed phase Co microcrystals with novel flowery morphology were prepared by solvothermal method,in which cobalt chloride was used as Co source and disodium ethylene diamine tetraacetate (EDTA) as complexing agent.The product were characterized by SEM,EDS,and XRD.In addition,effects of complexing agents and surfactants on morphology of the products were investigated.Results showed every flowery Co microcrystal was composed of many pieces of Co plate with uniform thickness of about 200 nm,which exhibited radiating arrangement from the centre.It was also found that EDTA played a crucial role in determining flowery structure of the sample.However,surfactants had no pronounced effects on morphology of the products.Based on the observations,mechanism of formation of flowery Co microcrystals was proposed.With action of EDTA,Co crystal nucleus grew into Co nanoplates at first;Co nanoplates diffused and assembled together as a result of strong magnetic interaction and steric hindrance,thus leading to the formation of flowery Co microcrystals.</FONT>