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Ligand‐Field Spectra and Structure of Nickel in Silicate Glasses
Author(s) -
TURNER WARREN H.,
TURNER JUDY A.
Publication year - 1972
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1972.tb11259.x
Subject(s) - silicate , alkali metal , nickel , aluminosilicate , octahedron , crystallography , chemistry , inorganic chemistry , crystal structure , materials science , biochemistry , organic chemistry , catalysis
The spectra of nickel dissolved in silicate and aluminosilicate glasses with alkali and alkaline‐earth modifiers were studied systematically as functions of composition, annealing and temperature, concentration of Ni 2+ , and redox conditions during melting. Although reducing conditions produced a gray scattering phase, only Ni 2+ was observed as a dissolved species. Several glasses contained one of two Ni 2+ species which corresponded to previously proposed 4‐ and 6‐coordinated species. Therefore, both octahedral and tetrahedral calculations could be made from directly observed bands free of overlapping. The results of these calculations suggest that the postulated tetrahedral species may instead be cubic (8‐coordinated). In addition, mixing of the Ni 2+ 3 T 1 g ( P ) level with Ni 2+ 4 p and/or ligand electron transfer bands was observed. Examination of the conditions that could produce the 8‐fold site on the basis of stereochemical and crystal‐chemical principles indicated that the packing requirements of the alkali‐oxygen, alkaline‐earth‐oxygen, and silicate polyhedra may preclude sites other than a large 6‐fold site or an even larger cubic (8) site. Thus, silicate glasses can be considered to consist of highly structured but disordered atomic arrangements.