Hemical Compounds - Lab Report Example

Compound

VSEPR formula

Predicted bond angle (⁰)

Polar? (yes/no)

H2O

MX2L2

104.5

yes

BeH2

MX2

180

no

H2S

MX2L2

91.5

yes

SO2

MX2L

120

yes

BF3

MX3

120

no

NF3

MX3

120

yes

IF3

MX3L2

120

yes

CH4

MX4

109.5

no

SF4

MX4L

120

yes

XeF4

MX4L2

90

no

PF5

MX5

120 and 90

no

SF6

MX6

90

no

3.2. Equilibrium geometry:

Compound

Bond angle (⁰)

Dipole moment (debye)

Polar? (yes/no)

H2O

103.98

1.86

yes

BeH2

180

0.0

no

H2S

93.38

0.97

yes

SO2

97.90

1.62

yes

BF3

120

0.0

no

NF3

120

0.2

yes

IF3

120

1.19

yes

CH4

109.47

0.0

no

SF4

86.36

0.632

yes

XeF4

90

0.0

no

PF5

90

0.0

no

SF6

90

0.0

no

4. Analysis:

            In some compounds (BeH2, BF3, NF3, IF3, XeF4, PF5 and SF6) the bond angles were the same between the predictions made by inspecting their Lewis structures and analysing the results of their equilibrium structures. In SF4 and SO2 the bond angles between the two measurements differed by a big margin (22.1⁰ for SO2 and 33.64⁰ for SF4). In H2O, H2S and CH4 the difference was small (0.52⁰ for H2O, 1.88⁰ for H2S and 0.03⁰ for CH­4).

            Because of these differences between the bond angles observed using Lewis structures and equilibrium geometry calculations, it is not possible to use only the direct inspection of Lewis structures to determine the bond angles of compounds. Polarities on the other hand can be determined by observing the Lewis structures. There are no changes in the polarities observed between the Lewis structures’ inspection and equilibrium geometry analysis.