Crystal growth and structure determination of oxygen-deficient Sr6Co5O15.
Crystal growth and structure determination of oxygen-deficient Sr6Co5O15.
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缺氧 Sr6Co5O15 的晶体生长和结构测定。
DOI：
10.1021/ic060862m
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发表时间：
2006
影响因子：
4.6
通讯作者：
Jianhua Lin
中科院分区：
文献类型：
--
作者：
Junliang Sun;Guobao Li;Zhaofei Li;L. You;Jianhua Lin
在过渡金属氧化物添加剂的存在下，使用K2CO3助熔剂获得了缺氧Sr6Co5O(15-δ)化合物的大单晶，即Sr6Co5O14.70和Sr6Co4.9Ni0.1O14.36。单晶结构测定表明，Sr6Co5O14.70和Sr6Co4.9Ni0.1O14.36的结构结晶在空间群R中，可以描述为一维共面CoO3多面体链和Sr阳离子链。与其他已知的2H-钙钛矿相关氧化物的多面体链由八面体（Oh）和三棱柱（TP）组成不同，Sr6Co5O14.70和Sr6Co4.9Ni0.1O14.36的结构包含Oh和中间多面体（IP），并且可归因于通式A6A'2B3O(15-delta)，其与已知的结构密切相关。 A6A'B4O15 通过 B 原子和 O3 三角形沿 c 轴移动而产生相位。对O3的进一步研究表明，这个氧位置分裂成两个独立的位置，分别对应于IP和TP的多面体几何形状。因此，结构中的多面体链应该更准确地描述为4Oh + TP和3Oh + 2IP的随机复合体。该模型用于解释磁性，但不是定量的。还对 Sr6Co5O14.70 和 Sr6Co4.9Ni0.1O14.36 进行了 4-D 结构分析，在 4-D 超空间群 R3m(00gamma)0s，gamma = p/k = 3/5 中具有相应的调制结构。通过考虑相同的4维超空间群R3m(00gamma)0s但不同的t相，我们可以理解Sr6Co5O14.70和Sr6Rh5O15之间的结构关系。
Large single crystals of oxygen-deficient Sr6Co5O(15-delta) compounds, i.e., Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36, were obtained by using K2CO3 flux in the presence of additives of transition metal oxides. The single-crystal structure determination shows that the structures of Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36 crystallize in the space group R and can be described as one-dimensional face-sharing CoO3 polyhedral chains and Sr cation chains. Unlike the other known 2H-perovskite-related oxides in which the polyhedral chains consist of octahedra (Oh) and trigonal prism (TP), the structure of Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36 contain Oh and intermediate polyhedra (IP) and can be attributed to a general structure formula A6A'2B3O(15-delta), which is closely related to the known A6A'B4O15 phases by shifting of a B atom and the O3 triangle along the c axis. Further study on O3 reveals that this oxygen position splits into two independent positions, corresponding to polyhedral geometry of IP and TP, respectively. Therefore, the polyhedral chain in the structure should be more precisely described as a random composite of the 4Oh + TP and 3Oh + 2IP. This model is used to interpret the magnetic properties, although not quantitatively. The 4-D structure analysis was also conducted for both Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36 with a commensurate modulated structure in a 4-D superspace group, R3m(00gamma)0s, gamma = p/k = 3/5. By considering the same 4-D superspace group R3m(00gamma)0s but different t-phases, one can understand the structure relationship between Sr6Co5O14.70 and Sr6Rh5O15.