if you had this complex ion [CoF6]^-3 would this ion absorb red or blue color and would you expect this complex to be high or low spin.

Answer 1

F^- is relatively low on the scale for CFSE, therefore, delta oct will be lower which results in a lower energy absorption, so it should absorb in the red since red is lower energy than blue. This same reasoning leads me to believe it would be a high spin complex.