Département Chimie des Matériaux Inorganiques, IPCMS, UMR 7504 (CNRS-UDS), 23 rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France.
Inorg Chem. 2010 Mar 15;49(6):3019-24. doi: 10.1021/ic9025552.
The synthesis and nuclear and magnetic structures from the powder diffraction of Co(II)(5)(OH)(6)(SeO(4))(2)(H(2)O)(4) and its deuterated analogues as well as their infrared spectral, thermal, and magnetic properties are reported. The nuclear structure consists of brucite-like cobalt hydroxide layers connected by ...OSeO(3)-Co(H(2)O)(4)-O(3)SeO... bridges. The two independent cobalt atoms within the layer are arranged in chains along the b axis creating an anisotropy within each layer. The interlayer distance (10.718 A) is the only parameter to increase compared to the sulfate analogue (10.273 A). The infrared spectra and thermal properties are similar to those reported for the sulfate analogue. Due to the ferromagnetic exchange between the nearest-neighbor cobalt atoms within the layer, satisfying the Goodenough-Kanamori rule, and the weak interlayer exchange, an overall ferromagnet is obtained. The ferromagnetic order at 9 K was confirmed by the ac susceptibilities, the saturation magnetization, and most importantly the enhancement of some Bragg diffraction peaks below the Curie temperature. The moments of all the cobalt atoms were found to be aligned along the b axis with a moment of 3.25(8) mu(B) each giving the best fit. The increase in layer distance and the electron density by replacing sulfur by selenium lowers the Curie temperature.
报道了 Co(II)(5)(OH)(6)(SeO(4))(2)(H(2)O)(4)及其氘代类似物的粉末衍射的合成、核和磁结构及其红外光谱、热和磁性质。核结构由类似于水镁石的钴氢氧化物层通过...OSeO(3)-Co(H(2)O)(4)-O(3)SeO...桥连接而成。层内的两个独立钴原子沿着 b 轴排列成链，在每个层内产生各向异性。层间距离（10.718 A）是唯一与硫酸盐类似物（10.273 A）相比增加的参数。红外光谱和热性质与硫酸盐类似物报道的相似。由于层内最近邻钴原子之间的铁磁交换，满足古德纳-坎纳莫利规则，以及弱的层间交换，获得了整体铁磁体。交流磁化率、饱和磁化强度以及最重要的居里温度以下一些布拉格衍射峰的增强证实了 9 K 时的铁磁有序。发现所有钴原子的磁矩都沿着 b 轴排列，每个磁矩为 3.25(8)mu(B)，给出了最佳拟合。通过用硒取代硫来增加层间距离和电子密度，降低了居里温度。
