CHEM 106 Lab 6 Practice Report

Lab 6: VSEPR and molecular shape “How does it look?”
Data Tables:
Part 1: Basic Shapes
Molecule Name Shape Predicted Bond angle Bond angle (Degrees)
PF6- Octahedral 90 89.4, 90.4, 89.8, 90, 90
BrF6 Octahedral 90 89.5, 90, 90,89.7
I3 Linear 180 180
In(CH3)3 Trigonal pyramidal 109.5 109.6, 109.4, 109.4
BeF42- tetrahedral 109.5 108.6, 109.7, 108.6,
109.7
NH4+ Tetrahedral 109.5 105.6,108, 109.5,114.9
SbF6- Octahedral 90 89,89.4,89.9,92.1,91.4


Part 2: Effects of lone pairs on molecular shape
Molecule Name Shape
XeF5 Square pyramidal
H 2O tetrahedral
CIF4 Square planar
SbBr52- Square pyramidal


Part 3: Effects of Lone pairs on bond angles
Molecule Predicted Actual Crystal Predicted angles Actual Angles
Geometry Structure
Di- seesaw seesaw 90 90.6,90.8,91.7
bromodimethylsel
enium
SO2 bent bent 120 113
NH3 Trigonal trigonal 109.5 101.3
Dichloro- Trigonal Trigonal 109.5 90.8, 100.4
diphenyl-selenium Bipyramidal Bipyramidal
Boric acid Trigonal planar Trigonal Planar 109.5 119.6,
119.9,120.4




Focus Questions:
1. What is VSEPR theory, and how can it be used to predict molecular shapes?
a. The VSEPR theory states that the atoms in a molecule will repulse each other.
Therefore, they will tend to assume the geometric shape that has the least
repulsion. The VSEPR theory helps us predict molecular shapes because it helps