Crystallographic Data. 140a. Lead Azide, Pb (N3) 2 (Form I)

May 1, 2002 - Low temperature photoluminescence of lead azide. J. Schanda , B. Baron , F. Williams. Journal of Luminescence 1974 9 (4), 338-342 ...
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L U M E 28, N O . 11, N O V E M B E R 1 9 5 6

1791

AY DIFFRACTION DATA

,I1Dimensions.

aa

= 8.62 A,, bo = 11.00 A,, co = 6.10

A.

irmula Weights per Cell. 4. Formula Weight. 105.14. Density. 1.211 grams per cc. (displacement), 1.211 grams per cc. (x-ray).

slowly without agitation over a period of several hours. Typical orystsls prepared in this manner are shown in Figures I and 2. The positions of the lead atoms in each of the polymorphic farms have been determined by Azaroff (1). Crystsk of Form I1 transform readily t o Form I in solution (Figure 3).

OPTICALPROPERTIES Refractive Indices (5893 A,, 25"C.), a

= 1.516, p = 1.528, 1.538. Optic Axial Angle. 2V = ( - ) 84"24' (calculated from a, 0,

y =

9"d " ) , _-_

O& Axial Plane. Perpendicular to 010 Acute Biseotrix. a. Extinction. a A e = 16" in itcute 8.

X-Ray Powder Diffraction Data d 6.81 5.33 5.12 4.83 4.65 4.30 4.08 3.75 3.43 3.37 3.26 3.14 2.98 2.90 2.73 2.66 2.57 2.46 2.41 2.39 2.35 2.23 2.04 1.990 1.905 1.850 1.795

hkl 110

1/Il 0.50 0.80 0.50 0.80 1.00

OIL

101 101 iii. 120

0.40 1.00 0.20 0.20 0.20

200 021

0.40 0.20 0.20 0.30 0.10 0.10

211 03_1

0.10b 0.20 0.10 0.10

12i

211 220

131 221 112

.

3oi . 23i.202 311 20! 141

d (Calod.! 6.78 5.33 5.12 4.83 4.64.4.6)

4.30 4.08 3.75 3.44 3.39 3.26 3.14 2.98 2.90 2.73 2.66 2.58.2.56 2.47 2.42 2.43

0.05 0.05

melt does not crystallize on cooling.

I

P r i n c i d Lines d 5.37 5.01 4.84 4.64 4.44

1/11

4.27

6

4.13 3.90 3.78 3.29

8

3.20 3.15 3.08 3.02 2.95

a

5

4 10 4 1vu,. Beta Angle.

107.5'