Crystalline & Amorphous solids - Solid State Video Lecture | Physical Chemistry

amorphous and crystalline solids
two dimensional
what's a crystalline solid consists of
large number of small crystals having a
definite geometrical shape crystals have
long-range order which indicate the
regular pattern of arrangement of
particles which repeated over the entire
crystal example NaCl sodium chloride
quartz containing infinite chain of SiO
4 units etc
anisotropy in crystal crystalline solids
have sharp melting point these are
anisotropic in nature which means that
some physical properties like refractive
index electrical resistance should
different values in different directions
because the arrangement of the particles
is different in different directions
two-dimensional structure of quartz plus
an amorphous solid in Greek amorphous
means no form consists of particles with
irregular shape the Constituent particle
has only short-range order
they have structures similar to that of
liquids example rubber plus etc
amorphous solids do not have sharp
melting point they melt over a range of
temperature so these can be molded and
blown into different shapes these can be
made crystalline by slow cooling their
melts some of these solids have a
tendency to flow very slowly so these
are also called pseudo solids or
supercooled liquids these are isotropic
in nature these exhibit same value of
any physical property in any direction
these solids have many applications in
our day-to-day life example amorphous
silicon as photovoltaic material for
converting sunlight to electrical energy