K_2NiF_4型结构的A_（2－x）Sr_xBO_4（A＝La，Dy，B＝Mn，Fe，Co，Ni）希土复合氧化物的合成

以典型的轻希土镧和重希上镝及碱土金属锶作为Ａ位离子，以过渡金属锰、铁、钴、镍作为Ｂ位离子，合成了Ｋ２ＮｉＦ４型结构的Ａ２－ｘＳｒｘＢＯ４希土复合氧化物．采用粉末Ｘ射线衍射技术考察了反应条件等因素对生成Ｋ２ＮｉＦ４型四方（Ｔ）结构相的影响．实验结果表明，四方结构的形成不仅与几何因素有关，而且与各组分的物理化学性质有关．各个不同的组成，生成四方相的温度范围也有所不同．适当地提高反应温度以及延长灼烧时间总是有利于高结晶态的Ｋ２ＮｉＦ４型结构相的形成．值得注意的是，过高的合成反应温度反而会引起四方结构的不稳定性以致破坏．

SYNTHESES OF RARE-EARTH COMPLEX OXIDES A_(2-x)Sr_xBO_4(A=La, Dy, B=Mn, Fe, Co, Ni) WITH K_2NiF_4 STRUCTURE

The tetragonal A2-xSrxBO4(A=La, Dy, B=Mn, Fe, Co, Ni) oxides with K2NiF4 structure have been synthesized by citric-complexing decomposition method, and investigated at various calcining temperatures and time under air by means of X-ray powder diffraction technique.The results of phase analysis indicated that the formation of T-structure was not only related to geometric factor, but also to the physical chemistry propertics of the components. Besides, an clcvated calcining tempcrature and prolonging calcining time were favorable for the formation of the single T-phase crystal. It was noticed that the K2NiF4 structure was unstable at over-high calcining temperature.