The 18 Electron Rule for Transition Metal Complexes

The video tutorial explains the 18 electron rule for transition metal complexes, comparing it to the octet rule. It provides a step-by-step algorithm for determining electron counts in complexes, using examples with iron and tungsten. The tutorial also discusses exceptions to the rule, such as square planar complexes, and emphasizes the importance of understanding ligand charges and electron contributions.

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

• To achieve a noble gas configuration

• To minimize the oxidation state of the metal

• To maximize the number of ligands

• To ensure the complex is thermodynamically stable

Why might a complex with more than 18 electrons be unstable?

• It lacks sufficient oxidation states

• It is thermodynamically unfavorable

• It has too many ligands

• It cannot form covalent bonds

Which step is NOT part of the algorithm to determine the electron count in a complex?

• Counting the number of protons in the metal

• Separating ligands from the metal

• Calculating the oxidation state of the metal

• Adding electrons from the metal and ligands

In the example of the iron complex with cyanide ions, what is the charge on the iron atom?

• +2

• +1

• 0

• -1

How many electrons does the cyclopentadienyl anion donate in the tungsten complex example?

• 4

• 8

• 2

• 6

What is the electron configuration ending for a neutral tungsten atom?

• 4S23D6

• 6S25D4

• 5S24D4

• 7S26D5

In the iron complex with a cyclopentadienyl anion, carbonyls, and an alkyne, what is the likely electron donation of the alkyne?

• 4 electrons

• 3 electrons

• 2 electrons

• 1 electron

What is a key exception to the 18 electron rule?

• Linear complexes

• Square planar complexes

• Tetrahedral complexes

• Octahedral complexes

Which of the following is NOT a common ligand charge convention mentioned?

• Alkyl ladines as neutral

• Alkyl ladines as 3 minus

• Alkyl ladines as 2 minus

• Alkyl ladines as 1 minus

What should be done if a discrepancy in electron counting is found with other sources?

• Ignore the discrepancy

• Recalculate using a different metal

• Adopt the new convention immediately

• Note the difference in approach