AMORPHOUS and
CRYSTALLINE
SOLIDS
GRADE XII - OLC
LEARNING COMPETENCIES
• Describe the structure of crystalline and
amorphous solid.
Amorphous
Crystalline
WHAT ARE THE TWO GENERAL
TYPES OF SOLIDS?
• What features can be used to distinguish a
crystalline solid from an amorphous solid?
The differences in properties of these two groups of
solids arise from the presence or absence of long
range order of arrangements of the particles in
the solid.
ARRANGEMENT of PARTICLES
The components of a solid can be arranged in two general ways:
CRYSTALLINE SOLID
• they can form a regular
repeating three-dimensional
structure called a crystal
lattice, thus producing a
crystalline solid’
AMORPHOUS SOLID
• they can aggregate with no
particular long range
order, and form an
amorphous solid (from
the Greek ámorphos,
meaning “shapeless”).
Crystalline solids are
arranged in fixed geometric
patterns or lattices.
Examples of crystalline solids are ice
and sodium chloride (NaCl), copper
sulfate (CuSO4), diamond, graphite,
and sugar (C12H22O11).
The ordered arrangement of their
units maximizes the space they
occupy and are essentially
incompressible.
EXAMPLES
Crystalline Solids (vocabulary)
Lattice
Unit cell
• is a three-dimensional
• is the smallest repeating
system of points
designating the positions
of the components
(atoms, ions, or molecules)
that make up a crystal
unit of a lattice
COMMON UNIT CELLS and LATTICES
Amorphous solids have a
random orientation of
particles.
Examples of
amorphous solids are
glass, plastic, coal, and
rubber.
They are considered
super-cooled liquids
where molecules are
arranged in a random
manner similar to the
liquid state.
EXAMPLES
Differences between AMORPHOUS and CRYSTALLINE
SOLIDS
AMORPHOUS SOLIDS
CRYSTALLINE SOLIDS
Particles (atoms, molecules or
Particles are randomly
a. Arrangement
ions) are closely packed and
arranged and have no ordered
of Particles
have an ordered threestructure.
dimensional structure.
Do not have sharp melting
b. Melting Point points; they melt over a wide
Sharp melting points
range of temperatures
c. Examples
Glass, rubber, and plastics
Diamond, graphite, NaCl,
CuSO4*5H2O, and sugar
FOR MORE INFORMATION…
More than 90% of naturally occurring and
artificially prepared solids are crystalline.
Minerals, sand, clay, limestone, metals, alloys,
carbon (diamond and graphite), salts (e.g. NaCl
and MgSO4), all have crystalline structures.
• They have structures formed by repeating three dimensional
patterns of atoms, ions, or molecules.
• The repetition of structural units of the substance over long
atomic distances is referred to as long-range order.
• Amorphous solids (e.g. glass), like liquids, do not have long
range order, but may have a limited, localized order in their
structures.
BEHAVIOR WHEN HEATEDCRYSTALLINE
• The presence or absence of long-range order in the structure of
solids results in a difference in the behavior of the solid when
heated.
• The structures of crystalline solids are built from repeating units
called crystal lattices. The surroundings of particles in the
structure are uniform, and the attractive forces experienced by
the particles are of similar types and strength.
BEHAVIOR WHEN HEATEDAMORPHOUS
• Amorphous solids soften gradually when they are heated.
They tend to melt over a wide range of temperature.
• This behavior is a result of the variation in the
arrangement of particles in their structures, causing
some parts of the solid to melt ahead of other parts.