Solid States Flashcards
Property of crystalline and amorphous
Defined geometrical structure Cleavage property Melting point Enthalpy of fusion Order range Anisotropy
Crystal lattice
A space lattice or a crystal lattice is a patter of points representing the location of motifs/basis (structural unit)
Characteristics of crystal lattice
1) each point in the crystal lattice is called lattice point, lattice site
2) each point represent a constituent particle (Ion, atom , molecule)
2) these point are joined by straight lines to bring light the geometry
Packing efficiency
FCC
Bcc
Sc
74%
68%
52.4%
Solids with appear amorphous but are crystalline
Polycrystalline solids
Most metals
Appear isotropic but are anisotropic
Isomorphous
2 crystals having a similar crystalline form
Eg znso4.7h2o mgso4.7h2oo
Polymorphic crystals
They exist in more than one crystalline form
Eg CaCo3: calcite, aragonite
ZnS Spharalite, Wurtzite
Unit cell
The smallest portion of a crystal lattice which when repeated it self in diff direction, create the whole lattice itself
Octahedral voids position
Edge centered and body centered
shows both schottky and frenkle defect
AgBr
Increase in preasure and temp changes what cn to what cn type
pressure: 6:6 (NaCl) to 8:8 (CsCl)
Temp : viceversa
noble gas arrangments and exception
fcc/ccp
ex: helium: hcp
planar triangular tetrahedral hexogonal bcc eg
ba2o3
sphaleite
ncal
cscl
Packing eff of diamond
34%
Z= 8
defect/ imperfection
any deviations/irregularites from a perfectly ordered arrangment of constituent particle
frenkel defect
dislocation defect cation dislocate to interstitial site no change in density large diff in atom size ZnS,AgCl, AgBr, AgI
schottky defect eg
Equal size
NaCl, AgBr, KCl, CsCl
defect colour
NaCl: yellow
LiCl: Pink
KCl: violet
compare schottky effect and Frenkel eff
shky eff appears more than frenkle eff cause is very less energy is needed
they all inc in no in temp, so are called Thermodynamics defect
Conductors
Insulators
Semi cont
4-7
- 20 to -10
- 6 to 4