The complex ion [Co(CO₃)₃]³⁻, an octahedral complex with bidentate carbonate ions as ligands, has one absorption in the visible region of the spectrum at 640 nm. From this information,
(a) Predict the color of this complex and explain your reasoning.
(b) Is the carbonate ion a weak- or strong-field ligand?
(c) Predict whether [Co(CO₃)₃]³⁻ will be paramagnetic or diamagnetic.