Fill in the blanks by choosing the appropriate word(s) from those given in the brackets…

Fill in the blanks by choosing the appropriate word(s) from those given in the brackets: [decreases, $\text{CN}^-$ ion, activation energy, catalyst, two, $\text{Fe}^{2+}$ ion, carbon, lattice energy, enzyme, five, double, halogen, triple, increases] The number of ions that will be produced when potassium ferrocyanide, $\text{K}_4[\text{Fe}(\text{CN})_6]$, dissolves in water is ____. This shows that ____ is the ligand in the coordination compound.