Question

predict the geometries of the following ion. sif$_{6}^{2 - }$ part 1 of 2 electron domain geometry select part 2 of 2 molecular geometry select

Explanation:

Step1: Determine the central atom

The central atom in $SiF_{6}^{2 -}$ is Si.

Step2: Calculate the number of electron - domains

Silicon has 4 valence electrons. Each F atom contributes 1 electron for bonding, and there are 6 F atoms. Also, the ion has a 2 - negative charge which adds 2 electrons. So the total number of valence electrons around Si is $4 + 6\times1+ 2=12$. The number of electron - domains (bonding pairs + lone pairs) around Si is $\frac{12}{2}=6$ (since each electron - domain has 2 electrons).

Step3: Determine electron - domain geometry

When the number of electron - domains around the central atom is 6, the electron - domain geometry is octahedral.

Step4: Determine molecular geometry

Since there are no lone pairs on the central Si atom (all 6 electron - domains are bonding pairs with F atoms), the molecular geometry is also octahedral.

Answer:

Part 1 of 2: Electron Domain Geometry: Octahedral
Part 2 of 2: Molecular Geometry: Octahedral