Question

I am trying to determine the point group of Fe2(CO)8 and am having difficulty with the bond angles and geometry. How would one go about this in a logical sense?

Answer 1

To determine the point group of Fe2(CO)8, consider its bond angles and geometry. Fe2(CO)8 has a Fe-O-O angle of approximately 130°. From the Lewis structure, each iron atom has a trigonal planar geometry, resulting in a D3h point group.

Step-by-step explanation:

In order to determine the point group of Fe2(CO)8, we need to consider the structure and symmetry of the molecule. Firstly, we can determine the bond angles by looking at the structure. Fe2(CO)8 consists of two iron atoms (Fe) and eight carbon monoxide (CO) ligands. The Fe-O-O angle is about 130° based on Figure 23.6.9.

For the overall geometry, we can use VSEPR theory and molecular geometry principles. From the Lewis structure, we can count the number of electron groups around each atom.

Each iron atom has 3 electron groups, which corresponds to a trigonal planar arrangement. This means that each iron atom has a geometry of AX3.

Considering the symmetry of the molecule, we can determine the point group. Based on the trigonal planar geometry of the iron atoms, the molecule has D3h symmetry. The D3h point group consists of elements such as three C3 rotations, three σv planes, and a horizontal refection plane. Therefore, the point group of Fe2(CO)8 is D3h.