Noreen Hanif
ASSIGNMENT 6

1. Used the peaks given in question 5 and then added 8 more but did not use the ones that had a shoulder on the left hand side. The result had a high figure of merit, 36.9 and all 20 peaks were indexed. Peaks used:

2q I (obs)
7.5 67
8.07 7727
10.25 3634
11.77 104
14.82 1731
15.05 557
16.09 199
16.64 108
16.9 448
17.15 1861
18.07 740
18.27 185
18.81 2587
19.36 1031
20.63 680
20.84 65
22.67 228
23.45 626
24.27 1793
24.41 135

a = 23.742 Å, b = 6.176 Å, c = 11.035 Å
a = 90°, b = 97.88°, g = 90°

Crystal system is monoclinic as a¹b¹c and a=g = 90°, b¹90°

2. Bravais lattice type will be mP because the crystal system is monoclinic and the lattice type is type is primitive.

3. From hkl program space group is P2/m which does not have screw axes or glide planes therefore there are no reflection conditions.

4. Space group is P2/m.

5.

2q   h   k   l     2q   h   k   l     2q   h   k   l
7.50  2  0  0   14.82  1  1  0   16.90  -2  0  2
8.07  0  0  1   15.05  4  0  0   17.15  1  1  1
10.25  -2  0  1   16.09  -4  0  1   18.07  4  0  1
11.77  2  0  1   16.64  -1  1  1   18.27  3  1  0

          a (Å) b (Å) c (Å) a (°) b (°) g (°)
Value  23.72951  6.17132  11.03174  89.9869  97.9013  90.0200
ESD  0.00928  0.00333  0.00518  0.0461  0.0176  0.0350

2qzero = -0.0135 ± 0.0053

The peaks are very weak in the high angle region so cannot include the high angle data and greater error is caused at high angles by the the diffractometer as collecting data.