Department of Physics, Banaras Hindu University, Varanasi, 221005, India.
Dalton Trans. 2011 Aug 7;40(29):7590-4. doi: 10.1039/c1dt10327j. Epub 2011 Jun 22.
The nanoparticles of CaMoO(4) : Eu(3+) (Eu(3+) = 0, 1, 3, 5, 7, 10 at. %) are prepared at low temperature (150 °C for 3 h) using urea hydrolysis in ethylene glycol. These are characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). From XRD study, it was found that the solubility limit of Eu(3+) ions at the Ca(2+) sites is up to 3 at. % and above this, phase segregation occurs. In combination with Rietveld analysis, its crystal structure was found to be tetragonal phase (space group I4(1)/a (88) and Z = 4 (number of CaMoO(4) formula units per unit cell). Unit cell parameters and bond distances are calculated. The average crystallite sizes of as-prepared, 500 and 900 °C heated samples are found to be 20, 35 and 70 nm, respectively. The lattice strain is found to be 0.003-0.005. From IR study, the bands at 820 and 441 cm(-1) are assigned to asymmetric stretching and bending vibrations of the MoO(4)(2-) tetrahedron, respectively. From TEM study, the shape of particle was found to be spherical. The high resolution TEM suggests a change in orientation of the crystal on annealing up to 900 °C.
采用乙二醇中尿素水解法在低温（150°C 下 3 小时）下制备了 CaMoO(4) : Eu(3+)（Eu(3+) = 0、1、3、5、7、10 原子%）纳米粒子。通过 X 射线衍射（XRD）、红外光谱（IR）和透射电子显微镜（TEM）对其进行了表征。从 XRD 研究中发现，Eu(3+) 离子在 Ca(2+) 位的溶解度极限高达 3 原子%，超过此值会发生相分离。结合 Rietveld 分析，其晶体结构被发现为四方相（空间群 I4(1)/a (88)，Z = 4（每个晶胞中 CaMoO(4) 分子式的数量）。计算了晶胞参数和键距。发现制备的、在 500°C 和 900°C 加热的样品的平均晶粒尺寸分别为 20、35 和 70nm。晶格应变被发现为 0.003-0.005。从 IR 研究中，820 和 441cm(-1)处的带分别被分配给 MoO(4)(2-)四面体的不对称伸缩和弯曲振动。从 TEM 研究中发现，粒子的形状为球形。高分辨率 TEM 表明，在退火至 900°C 时，晶体的取向发生了变化。
