Which geometry is most commonly observed for coordination complexes with a coordination number of 4?

• A. Trigonal bipyramidal
• B. Tetrahedral
• C. Square planar
• D. Octahedral

Answer: (B)

Verified step by step guidance

1. Understand that the coordination number refers to the number of ligand atoms directly bonded to the central metal atom in a coordination complex.
2. Recognize that for coordination number 4, the two most common geometries are tetrahedral and square planar.
3. Recall that tetrahedral geometry has bond angles of approximately 109.5° and is common for many metal complexes, especially those with d10 or d0 electron configurations.
4. Know that square planar geometry has bond angles of 90° and is typically observed in certain d8 metal complexes, such as Pt(II) and Ni(II).
5. Conclude that among the options given, tetrahedral geometry is the most commonly observed for coordination number 4 complexes overall, while square planar is more specific to certain metals and electronic configurations.