Accession Number : ADA321991

Title :   The Oxidation State of Ni in the Nickel Oxide Electrode and Related Nickel Oxide Compounds: II. Geometric Evidence.

Descriptive Note : Technical rept.,

Corporate Author : GEORGE WASHINGTON UNIV WASHINGTON DC DEPT OF CHEMISTRY

Personal Author(s) : Sambe, H. ; Nabi, T. M. ; Ramaker, D. E.

PDF Url : ADA321991

Report Date : JAN 1997

Pagination or Media Count : 30

Abstract : The electronic structures of the nickel oxide electrode (NOE), NiOx(OH)(2-x) for x=0-1.6 and the related nickel oxide materials including the NiO- LiNiO2 - NiO2 series and the 'Ni(4+)' compounds, KNiO2(IO4) and BaNiO3, have been investigated utilizing geometric data such as the Ni-OH and Ni-O bond lengths published in the literature. The electronic structures deduced from these bond lengths agree with those found using spectroscopic data, which were presented in the preceding paper. In addition, the observed shortening of the Ni-O bond length in the NiO - LiNiO2 - NiO2 series is shown to arise from covalent shortening. The implications of this newly proposed electronic structures are as follows: (i) the charging reaction for the NOE can be viewed as OH(-) (Ni(2+)) --> O(-) (Ni(2+)) + H()+ + e(-), where (Ni(2+)) reminds us that the OH(-) and O(-) anions are attached to the Ni(2+) ion, which remain unchanged; (ii) the electron conduction in the charged NOE is in the oxygen layer; and (iii) the coloration of the NOE upon charging is due to the 3d (Ni(2+)) --> 2p (O(-)), metal-to-oxygen, charge transfer in the charged NOE.

Descriptors :   *MATERIALS, *OXIDATION, *OXIDES, *ELECTRODES, *GEOMETRY, *NICKEL COMPOUNDS, IONS, METALS, CONDUCTIVITY, SPECTROSCOPY, LAYERS, STRUCTURAL PROPERTIES, COVALENT BONDS, ELECTRONIC EQUIPMENT, OXYGEN, LITHIUM, CHEMICAL BONDS, ELECTRONS, CHARGE TRANSFER, BONDING.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE