What is the typical bond angle between tetrahedral, sp3-hybridized carbon compounds?

• A. 90°
• B. 109.5°
• C. 120°
• D. 180°

Answer: (B)

Four electron domains about a carbon atom arrange themselves in a tetrahedral geometry to minimize repulsion, and the ideal angle between any two bonds in a regular tetrahedron is about 109.5 degrees. This comes from the way sp3 hybrids distribute toward the corners of a tetrahedron, giving bond directions that are 109.47° apart. Therefore, the typical bond angle for tetrahedral, sp3-hybridized carbon compounds is about 109.5°. In real molecules, small deviations can occur due to substituent effects or ring strain, but 109.5° is the standard reference. The other angles correspond to different geometries (90° for certain octahedral-like or square arrangements, 120° for trigonal planar, 180° for linear), not to tetrahedral carbon.