Q110CP - Chemistry: Molecular Nature Of Matter And Change

Question

How many different formulas are there for octahedral complexes with a metal M and four ligands A, B, C, and D? Give the number of isomers for each formula and describe the isomers.

Step-by-Step Solution

Answer

a) The electrons are buried in the inner  5f-subshell.

b) Inner transition elements form ions by removing electrons from s, d, and f subshells, and transition elements form ions by removing electrons from s and d subshells.

Step 1: Given Information

Octahedral Complexes with a metal M and ligands A, B, C, and D.

Step 2: Octahedral complexes

Octahedral complexes describe the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron.

Step 3: Describe the isomers

Constitutional (structural) isomers - same formula, differently connected atoms; they can occur in two types:

• Coordination isomers - occur when the structure of the whole compound is the same, but the structure of complex ions differs.
• Linkage isomers - occur when the structure of the complex ion is the same, but the donor atom that which ligand uses is different.

Stereoisomers - have the same connections between atoms, but the atoms have different spatial arrangements; they occur in two types:

• Geometric (cis-trans) isomers - different spatial arrangements of atoms or groups, relative to the central metal ion.

• Optical isomers - occur when a molecule cannot be superimposed with its mirror image.

Octahedral complexes are formed when six ligands are bonded with the central metal ion.

Step 4: Different formulas are there for octahedral complexes

$\left[{\mathrm{MA}}_3\mathrm{BCD}\right]$

$\left[{\mathrm{MABC}}_3\mathrm{D}\right]$

$\left[{\mathrm{MABCD}}_3\right]$

$\left[{\mathrm{MA}}_2{\mathrm{B}}_2\mathrm{CD}\right]$

$\left[{\mathrm{MA}}_2{\mathrm{BCD}}_2\right]$

$\left[{\mathrm{MAB}}_2{\mathrm{C}}_2\mathrm{D}\right]$