Discuss what influence temperature has on molecular motions andhow it would impact the reaction in Part II.
Part II. Temperature Dependence in a Complex IonEquilibriumMetal ions such as Co2+ will form complex ions, whereligands surround the metal ion. A ligand
is either a molecule or ion that donates electron density to themetal ion to form a bond.Examples of ligands include H2O, NH3, Cl-,and OH-. CoCl2(H2O)2 is a complex metal ion withtwo Cl- (chloro)and two H2O (aqua) ligands surrounding the Co2+ in a tetrahedralgeometry.Co(H2O)6
2+ is also a complex ion with six water molecules (aqua ligands)surrounding the
central metal ion, Co2+, in an octahedral geometry.
In aqueous solution, we can observe the conversion between thetetrahedral complex ion,
CoCl2(H2O)2, which is blue, and the hydrated octahedral complexion, Co(H2O)6
2+, which is pink,
according to the following equilibrium.
CoCl2(H2O)2 + 4 H2OÂ Â Co(H2O)6
2+Â Â + 2 Cl-
     blue       pink
By dissolving CoCl2∙(H2O)6 in methanol, the solution obtained isbetween blue and pink.
