What is the geometry for six bonded atoms and no lone pairs?

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

Answer: (B)

Think about how many electron regions surround the central atom. Each bond is one region of electron density, and lone pairs count as separate regions too. The geometry that minimizes repulsion for six bonding regions and no lone pairs is the octahedral arrangement, where the six ligands point to the corners of an octahedron. Bond angles between adjacent bonds are 90°, with opposite bonds at 180°. If lone pairs were present, the shape would change (for example, five bonding regions with one lone pair gives a square pyramidal shape, while four bonding regions with two lone pairs gives square planar), but with six bonds and no lone pairs, the octahedral geometry is the correct description.