What is the coordination number of the metal in each of the following complexes?
(d) [ZrF8]4-
(e) [Fe(EDTA)(H2O)]-

Verified step by step guidance

1. 1. The coordination number of a metal in a complex is the number of ligand electron pairs surrounding that metal ion. In other words, it's the number of atoms directly bonded to the metal ion.
2. 2. For the complex [ZrF8]4-, the ligand is F- (fluoride ion). Each fluoride ion can form one bond with the metal ion. Since there are 8 fluoride ions in the complex, the coordination number of Zr is 8.
3. 3. For the complex [Fe(EDTA)(H2O)]-, the ligands are EDTA and H2O. EDTA is a hexadentate ligand, meaning it can form 6 bonds with the metal ion. H2O is a monodentate ligand, meaning it can form one bond with the metal ion. Therefore, the coordination number of Fe in this complex is 6 (from EDTA) + 1 (from H2O) = 7.

Key Concepts

Coordination Number

The coordination number refers to the number of ligand atoms that are directly bonded to a central metal atom in a coordination complex. It is a crucial concept in coordination chemistry, as it helps determine the geometry and stability of the complex. For example, a coordination number of 6 typically leads to an octahedral geometry, while a coordination number of 4 can lead to either tetrahedral or square planar geometries.

Ligands

Ligands are ions or molecules that can donate a pair of electrons to a central metal atom to form a coordination complex. They can be classified as monodentate, bidentate, or polydentate based on the number of donor atoms they possess. In the given complexes, fluoride ions (F-) and the EDTA ligand are examples of ligands that coordinate with the metal center, influencing the overall structure and properties of the complex.

Complex Ions

Complex ions are charged species consisting of a central metal atom bonded to one or more ligands. They can carry a positive or negative charge depending on the nature of the metal and the ligands involved. Understanding complex ions is essential for determining the coordination number, as it directly relates to how many ligands surround the metal center, as seen in the complexes [ZrF8]4- and [Fe(EDTA)(H2O)]-.