Z-Matrices

Question 1

a. cis-Cl₂C₂H₂

x
x 1 1.0
c 1 b1 2 90.0
c 1 b1 2 90.0 3 180.0
cl 3 b2 1 a2 2 0.0
cl 4 b2 1 a2 2 0.0
h 3 b3 1 a3 2 180.0
h 4 b3 1 a3 2 180.0

b1 0.70
b2 1.76
b3 1.09
a2 120.0
a3 120.0

b. trans-Cl₂C₂H₂

x
x 1 1.0
c 1 b1 2 90.0
c 1 b1 2 90.0 3 180.0
cl 3 b2 1 a2 2 0.0
cl 4 b2 1 a2 2 180.0
h 3 b3 1 a3 2 180.0
h 4 b3 1 a3 2 0.0

b1 0.70
b2 1.76
b3 1.09
a2 120.0
a3 120.0

c. C(NH₂)₂ (parent acyclic NHC, planar)

c
x 1 1.0
n 1 b1 2 a1
n 1 b1 2 a1 3 180.0
h 3 b2 1 a2 2 0.0
h 4 b2 1 a2 2 00.0
h 3 b3 1 a3 2 180.0
h 4 b3 1 a3 2 180.0

b1 1.52
b2 1.0
b3 1.0
a1 120.0
a2 120.0
a3 120.0

d. S₈ (crown geometry)

x
x 1 1.0
s 1 b1 2 a1
s 1 b1 2 a2 3 45.0
s 1 b1 2 a2 3 -45.0
s 1 b1 2 a1 3 90.0
s 1 b1 2 a1 3 -90.0
s 1 b1 2 a2 3 135.0
s 1 b1 2 a2 3 -135.0
s 1 b1 2 a1 3 180.0

b1 2.0
a1 70.0
a2 110.0

e. SOCl₂

s
x 1 1.0
o 1 b1 2 a1
cl 1 b2 2 a2 3 d2
cl 1 b2 2 a2 3 -d2

b1 1.75
b2 2.0
a1 110.0
a2 110.0
d2 120.0

Question 2

a.

Point Group = C₂

b.

Point Group = C_S