Crystallography

Question 1

crystal =

Answer 1

lattice+motif

Question 2

arrangement of atoms at each lattice point

Answer 2

motif / basis

Question 3

lattice

Answer 3

An infinite periodic array of points in space with each point having identical surroundings.

Question 4

primitive unit cell

Answer 4

contains single lattice point

Question 5

Bravais lattices

Answer 5

are the distinct lattice types generated by the discrete translation operations given by:
r=ka+lb+mc

Question 6

2D bravais lattices

Answer 6

5: oblique-p lattice, rectangular - lattice, rectangular c-lattice, square-p lattice, hexagonal-p lattice

Question 7

3D Bravais lattices: Lattice centerings

Answer 7

P- primitive
I - body centered
F - Face centered
A,B,C - base centered 
R - rhombohedral

Question 8

3D Bravais lattices

Answer 8

Cubic: a=b=c α=β=γ=90°
Simple Body-Centered Face-Centered
P I F

Tetragonal a=b≠c α=β=γ=90°
Simple Body-Centered
P I

Orthorhombic
a≠b≠c α=β=γ=90°
Simple Body-Centered Base-Centered Face-Centered
P I C F

Rhombohedral (trigonal) a=b=c α=β=γ≠90°
Simple
P

Hexagonal a=b≠c α=β=90°, γ=120o
Simple
P

Monoclinic a≠b≠c α=γ=90°≠β
Simple Base-Centered
P C

Triclinic a≠b≠c α≠β≠γ≠90°
Simple
P

Question 9

Miller indices

Answer 9

define families of directions

Question 10

Direction

Answer 10

Determine the length of the projections of the direction on the three axes of the unit cell dimensions.
Reduce to smallest integers by dividing by a common factor.

Question 11

square bracket

Answer 11

miller indices for single direction

Question 12

miller indices for single direction bracket

Answer 12

square [ ]

Answer 13

set of families of directions

Question 14

set of families of directions

Question 15

distance between planes

Answer 15

lattice spacing

Question 16

(hkl)

Answer 16

miller indices of families of planes

Question 17

miller indices of families of planes

Answer 17

(hkl)

Question 18

Defining a plane

Answer 18

write down intercepts with axis in terms of unit vector

express as fractions of unit cell length

Question 19

{hkl}

Answer 19

set of families of planes

Question 20

set of families of planes

Answer 20

{hkl}

Question 21

Zone law

Answer 21

If [uvw] lies in (hkl) then: hu + kv + lw = 0

Question 22

Zone axis

Answer 22

direction at which 2 families of planes intersect = 
u = (k1l2 - k2l1)
v = (l1h2 - l2h1) 
w = (h1k2 - h2k1) 
cross product of miller indices!