# Chapter16-Structure of Solids¶

## Ex1-pg483¶

In [7]:
import math
##Example 16.1
##calculation of density

##given values
a=3.36*10**-10;##lattice constant in m
M=209.;##atomicmass of polonium in kg
z=1.;##no of atom
##calculation
d=z*M/(N*a**3)

print'%s %.2f %s'%('density (in kg/m^3) is',d,'');

density (in kg/m^3) is 9152.34


## Ex2-pg483¶

In [3]:
import math
##Example 16.2
##calculation of no of atoms

##given values
a=4.3*10**-10;##edge of unit cell in m
d=963.;##density in kg/m**3
M=23.;##atomicmass of sodium in kg

##calculation
z=d*N*a**3./M;

print'%s %.2f %s'%('no of atoms is',z,'');

no of atoms is 2.00


## Ex3-pg483¶

In [4]:
import math
##Example 16.3
##calculation of distance

##given values
z=4.;##no of atoms in fcc
d=2180.;##density in kg/m**3
M=23+35.3;##atomicmass of sodium chloride in kg

##calculation
a1=z*M/(N*d);
a=a1**(1/3.);
l=a/2.;##in m

print'%s %.2f %s'%('distance between adjacent chlorine and sodium atoms in armstrong is',l*10**10,'');

distance between adjacent chlorine and sodium atoms in armstrong is 2.81


## Ex4-pg495¶

In [6]:
import math
##Example 16.4
##calculation of interatomic spacing

##given values
alpha=30*math.pi/180.;##Bragg angle in degree
h=1;
k=1;
l=1;
m=1;##order of reflection
x=1.75*10**-10;##wavelength in m

##calculation
d=m*x/(2.*math.sin(alpha));
a=d*math.sqrt(h**2+k**2+l**2.);##in m

print'%s %.2f %s'%('interatomic spacing in armstrong is',a*10**10,'');

interatomic spacing in armstrong is 3.03