...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Zeitschrift fur Anorganische und Allgemeine Chemie >CaNa[Cr(OH)_6] - A Layered Hydroxochromate(III) with Ordered Brucite Structure and its Thermal Decomposition
【24h】

CaNa[Cr(OH)_6] - A Layered Hydroxochromate(III) with Ordered Brucite Structure and its Thermal Decomposition

机译：CANA [Cr（OH）_6] - 具有有序布鲁石结构及其热分解的分层羟铬酸盐（III）

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Green single-crystals of the hydroxochromate(III) CaNa[Cr(OH)_6] were grown under highly alkaline hydrothermal conditions at about 200 °C. The starting materials Ca(NO_3)_2·6H_2O and Cr(NO_3)_3·9H_2O were reacted in a mixture of water and sodium hydroxide with the molar ratio of 2.8:1. CaNa[Cr(OH)_6] crystallizes in the non-centrosymmetric trigonal space group R3 with the lattice parameters a = 583.86(2) pm and c = 1428.73(6) pm [T = 100(1) K]. Characteristically, the crystals are reverse-obverse as well as inversion twins. The crystal structure is a stack of uncharged metal hydroxide layers, which can be regarded as a cation-ordered rhombohedral variant of the Mg(OH)_2 (brucite) structure type. The oxidation state of chromium(III) and its coordination by hydroxide groups was confirmed by UV/Vis and IR spectroscopy, respectively. Temperature-dependent magnetic measurements revealed paramagnetic behavior with an effective moment of 3.82 μ_B per chromium atom. The thermal decomposition of CaNa[Cr(OH)_6] takes place at about 225 °C, where the fast elimination of 1.5 equivalents of water is followed by the oxidation of chromium(III) to chromium(VI). Upon further heating to 1000 °C and 1200 °C, the intermediate decomposition products CaCrO_4 and Na_2CrO_4 transform into the oxochromates(V) Ca_5(CrO_4)_3O_(0.5) and Ca_3(CrO_4)_2, respectively.
机译：在大约200°C的高碱性水热条件下生长了氢氧化铬酸盐（III）CaNa[Cr（OH）6]的绿色单晶。起始材料Ca（NO_3）2·6H_2O和Cr（NO_3）3·9H_2O在水和氢氧化钠的摩尔比为2.8:1的混合物中反应。CaNa[Cr（OH）_6]在非中心对称三角空间群R3中结晶，晶格参数a=583.86（2）pm和c=1428.73（6）pm[T=100（1）K]。典型的是，这些晶体是正反面和反转孪晶。晶体结构是一堆不带电荷的金属氢氧化物层，可以认为是Mg（OH）2（水镁石）结构类型的阳离子有序菱形变体。通过紫外可见光谱和红外光谱分别证实了铬（III）的氧化状态及其与羟基的配位。随温度变化的磁测量显示顺磁行为，每个铬原子的有效磁矩为3.82μu B。CaNa[Cr（OH）U 6]的热分解发生在约225°C的温度下，其中快速消除1.5当量的水，然后将铬（III）氧化为铬（VI）。在进一步加热到1000°C和1200°C时，中间分解产物CaCrO_4和Na_2CrO_4分别转化为氧铬酸盐（V）Ca_5（CrO_4）_3O_（0.5）和Ca_3（CrO_4）_2。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号