Electron Counting in Transition Metal Complexes

The video tutorial explains the 18 electron rule, a guideline for determining the stability of transition metal complexes based on electron count. It compares this rule to the octet rule and provides a step-by-step algorithm for calculating electron counts in complexes. Examples with iron and tungsten complexes illustrate the application of the rule. The tutorial also discusses exceptions, such as square planar complexes, and mentions alternative electron counting conventions.

What is the primary goal of the 18 electron rule in transition metal complexes?

• To achieve a noble gas configuration

• To maximize the number of ligands

• To minimize the oxidation state of the metal

• To ensure the complex is thermodynamically stable

Which step is NOT part of the algorithm for determining the electron count in a complex?

• Separating ligands from the metal

• Calculating the oxidation state of the metal

• Counting the number of protons in the metal

• Adding electrons from the metal and ligands

In the example with an iron atom and six cyanide ions, what is the charge on the iron atom?

• 0

• 1+

• 2+

• 3+

How many electrons does a cyclopentadienyl anion donate in a complex?

• 6 electrons

• 8 electrons

• 2 electrons

• 4 electrons

What is the oxidation state of tungsten in the example with a cyclopentadienyl anion, three trimethyl phosphines, and two chlorides?

• +4

• +5

• +3

• +2

In the example with an iron center, cyclopentadienyl anion, two carbonyls, and an alkyne, how many electrons does the alkyne likely donate?

• 1 electron

• 2 electrons

• 3 electrons

• 4 electrons

What should you do if you encounter a discrepancy in electron counting with other sources?

• Recalculate using the octet rule

• Adopt the new convention immediately

• Ignore the discrepancy

• Note the difference in approach

Which type of complex is an exception to the 18 electron rule?

• Tetrahedral complexes

• Octahedral complexes

• Linear complexes

• Square planar complexes

What is the typical electron count for stable square planar complexes?

• 18 electrons

• 16 electrons

• 14 electrons

• 20 electrons

Why is it important to memorize the electron contributions of common ligands?

• To avoid using the 18 electron rule

• To increase the oxidation state of metals

• To simplify the electron counting process

• To ensure all complexes are unstable