Solid State 1

Solid State 1

1. Crystalline solids

   • substances having same crystalline structure are called isomorphous
   • single substance that crystallizes in two or more forms under different conditions are called polymorphous
   • true solids
   • may or may not be isotropic
   • heat of fusion -definite depends on- arrangement of particles
   • characteristics shape due to orderly regular long-range arrangement of constituent particle
   • homogeneous solid in which constituent particles atoms ions are molecules are arranged in a definite repeating pattern
   • classification
     • molecular solids
     • ionic solids
     • metallic solids
     • covalent solids
       • high melting point and depending upon available availability of mobile electrons - conductors / insulators
         • examples- Diamond graphite and fullerene
           • MP of diamond 3550 degree Celsius
           • graphite is used as lubricant &it is also used in Ribbons for printing in computers and typewriters, in lead pencils.
           • fullerene + potassium---> K35 C60- superconductor at 18 Kelvin, tubes of fullerene + graphite> nanotubes >used as high strength materials, electric conductors, molecular sensors, semiconductors
           • fullerene- soccer ball- Hollow sphere- C60.

2. amorphous solids

   • irregular shape due to short range orderly arrangement
   • pseudo solids or cooled liquids
   • isotropic like liquids
   • heat of fusion is not definite
   • substances that appear like solids but do not have well developed perfectly ordered crystalline structure