Periodicity Flashcards
(30 cards)
what is a lattice point
points in a periodic pattern that all have identical environments
what is a lattice
the periodic collection of lattice points
describes periodic nature of the pattern
what is a unit cell
the smallest unit that generates the entire pattern
what is a primitive lattice
it has no atom in the centre of the unit cell
what is a centred lattice
it has an atom in the middle of the unit cell
where does the alpha angle lie
between b and c axis
where does beta angle lie
between a and c axis
where does angle gamma lie
between a and b axis
which is the a axis
the x axis side to side
what is the c axis
the z axis u and down
what is the b axis
the y axis into the page
where is the a face of a unit cell
the b and c axes
where is the b face of a unit cell
the a and c axes
where is the c face of a unit cell
the a and b axes
what are the seven crystal systems
triclinic monoclinic orthorhombic tetragonal rhombohedral hexagonal cubic
what are the parameters for triclinic
all parameters are independent
what are the parameters for monoclinic
the axis are independant alpha and gamma are both 90 whereas beta is not 90
what are the parameters for orthorhombic
independant axes
alpha beta and gamma are all 90
what are the parameters for tetragonal
a and b are the same but different to c
alpha beta and gamma are all 90
what are the parameters for rhombohedral
all axes are the same
alpha and beta are 90 but gamma is not
what are the parameters for hexagonal
a and b are the same but different to c
alpha and beta are 90 and gamma is 120
what are the parameters for cubic
a b and c are the same
alpha beta and gamma are all 90
what is P in 3D lattice types
primitive
what is C in 3D lattice types
additional lattice points at the centre of the c face
