The effect of distortion on the spin allowed ligand field bands of the spectrum of tetrahedral nickel(II)

✍ Scribed by W.Ewen Smith

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 328 KB
• Volume: 38
• Category: Article
• ISSN: 1386-1425
• DOI: 10.1016/0584-8539(82)80035-4

✦ Synopsis

The effect of distortion and of changes in coordination on the ligand field spectrum of tetrahedral nickel in solution and in single crystals at temperatures down to 10 K is described. Dilution of a solution of NiCI~-produces a change from tetrahedral to five-coordination. The spectrum of the intense 3 TI(3F)_.> 3 Tl(3p) transitions has a characteristic double-peaked shape which, in some distorted compounds, is more pronounced at 10 K than at room temperature. By contrast, an undistorted NiCi4 2-ion produced a different spectrum with more fine structure at 10 K. This pattern is consistent with previous studies and supports the suggestion that the shape of these bands in tetrahedral nickel is due to a dynamic Jahn-Teller effect which is frozen out as the temperature is lowered. The 3T~(3F)~3A2(3F) transition of the undistorted NiCI~-ion is well resolved and progressions on vt, v2 and v4 are observed. The Raman and i.r. spectra were also recorded for this species and there is good agreement between the ground-state vibrational frequencies and the vibronic intervals.