Multiple choice

Which of the following geometries is possessed by complex Fe(CO)5?

  1. Square planar

  2. Tetrahedral

  3. Trigonal planar

  4. Trigonal bipyramidal

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Fe(CO)5 is iron pentacarbonyl, a neutral coordination complex. With five CO ligands around a central metal ion, the only stable geometry that minimizes repulsion while satisfying the 18-electron rule is trigonal bipyramidal. Square planar would require only 4 ligands, tetrahedral geometry with 5 ligands is unstable, and trigonal planar only accommodates 3 ligands.