Origin of the Yellow Color of Complex Nickel Oxides 

George R. Rossman
 Division of Geological and Planetary Sciences
California Institute of Technoogy
Pasadena, CA  91125

Robert D. Shannon, Robert K. Waring
Central Research and Development Department
E.E> du Pont de Nemours & Co.
Wilmington, Delaware  19898


Single-crystal optical absorption spectra of NiO, NiTiO3, NiWO4, NiV2O6, NiNb2O6, Ni2SiO4, Ni3V2O8, LiNiPO4, Li2Ni2Mo3O12, SrNiTeO6, LiScSiO4:Ni, MgSiO3:Ni, and (Mg,Ni)2SiO4, are presented or the purose of comparing the spectra of yellow and green Ni2+ compounds. Powder spectra of NiTiO3, NiWO4, NiV2O6, NiNb2O6, and Ni3V2O8 in the ultraviolet region help elucidate the more intense charge tranfer bands. Bright yellow color results when Ni2+ is in a six-coordinated site significantly distorted from octahedral symmetry. Increased absorption intensity occurs when the metal ion d-d bands are in proximity to an ultraviolet charge transfer band.

last updated: 23-May-2019