Oxidation State of Cobalt in the NaxCoO2-δ·yH2O Superconductor
Oxidation State of Cobalt in the NaxCoO2-δ·yH2O Superconductor
复制标题
NaxCoO2-δ·yH2O超导体中钴的氧化态
DOI：
10.1021/cm035298h
复制
发表时间：
2004
影响因子：
8.6
通讯作者：
H. Yamauchi
中科院分区：
文献类型：
--
作者：
M. Karppinen;Isao Asako;T. Motohashi;H. Yamauchi
在这里，我们提出了精确的湿化学氧化还原分析结果，表明新发现的 CoO2 层超导体 NaxCoO2·yH2O（x ≈ 0.36，y ≈ 1.3）中钴的氧化数为 ∼3.46。该值明显低于根据 Na 与 Co 化学计量比 x 确定的值所预期的值 (∼3.64)。 Co 氧化态的“低于预期”值也可以用氧空位或过量质子的存在来解释。此外，结果表明该相不应被视为空穴掺杂 CoIII 晶格，而不是电子掺杂 CoIV 晶格。
Here we present results of accurate wet-chemical redox analyses revealing that the oxidation number of cobalt in the newly discovered CoO2-layer superconductor, NaxCoO2·yH2O (x ≈ 0.36, y ≈ 1.3) is ∼3.46. This value is significantly lower than the one (∼3.64) expected on the basis of the value determined for the Na to Co stoichiometry ratio, x. The “lower-than-expected” value for the Co oxidation state may be alternatively explained by the presence of oxygen vacancies or excess protons. Moreover, the result implies that rather than an electron-doped CoIV lattice the phase should be considered as a hole-doped CoIII lattice.