中文摘要：

以醋酸钙和尿素为原料,在无添加剂的条件下采用微波水热法合成技术,直接制得了高度对称的双头矛状、双头扁平铲形、拉长六边形、拉长四边形、侧表面为六边形的多面体和六瓣花状等奇异形貌的碳酸钙晶体,利用扫描电子显微镜（SEM）、X射线衍射仪（XRD）、傅里叶红外光谱仪（FT-IR）等对样品进行了表征,并对碳酸钙晶体的形成过程进行了分析。结果表明醋酸钙用量、尿素用量和微波辐照能量对碳酸钙晶体的结构与形貌具有重要调控作用。

英文摘要：

The unusual high symmetrical double dagger-like, double flat-like, elongated hexagonal plateqike, elongated parallelogram, polyhedron with hexagon as lateral face, six petals flower-like CaCO3 polymorphs were prepared directly without any additives by the microwave-assisted hydrothermal synthesized method, using calcium acetate and urea as the raw materials. The obtained CaCO3 samples were characterized by means of scanning electron microscope （SEM）, X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）. The formation process of CaCO3 polymorphs was also discussed. It was showed that, the structure and morphology of CaCO3 crystals were well controlled by the use level of calcium acetate and urea, and microwave power.