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
doping
and types
adding an appropriate amt of suitable impurities to inc the conductivity of intrinsic semiconductors
ntype, p type
application of n type p type semicdt
a diode is a combination of p and n type are used as rectifiers
transistors are the sandwitch of npn or pnp which used to amplify or dedect raidio or audio signals
solar cell is a useful photodiode
transition temp
temp at which sub start behaving as supercoductors
mostly 2k to 5k
paramagnetic
weakly, temarory attraction
one or more unpaired electrons
lost their magnetism in absence of magnetic feild
O2, CU 2+, Fe3+. cr3+
Diamagnetic
weakly repeled by magnetic field
no unpaired electrons
zero magnetic moment
h2o, nacl, c6h6
Feromagnetic
permanent magnetism , eve in absence of magnetic field
unpaired erectron are 1D oreinted
Fe, Ni, Co, Gd, CrO2
antiferomagnetic
expected to posess para or fero but has 0 net magnetic moment due to equal no of domains being in opp direction
MnO
Ferrimagnetic
expected to have large magnetism but has small due to the unequal no of domains in opp direction
Fe3O4 magnetite
ferites like mgfeo2 znfe2o4
on heating these become paramagnetic 850k
curie temp
temp above which feromagnetism is not observed
coordination no
The number of nearest neighbours of a particle in a closed arrangment are called its coordination number.
What is responsible for the malleability property of metallic solids
Sea of electrons
Boron nitride
Solid type
Covalent/network
C-c bond in diamond and graphite
Diamond: 154pm
Graphite : 141.4 (—)
340pm (I)
Amorphas solids eg
Bakelite
Neoprene
Melamine
Formaldehyde
CS2 solid type
Molecular
Washing soda solid type
Ionic
CCl4 Co2 solid type
Molecular
AiN solid type
Covalent
Corborundum
Name / solid type
SiC covalent
Corrundum
Ionic
diamagnetic eg
NaCl C6H6 H2OB
Paramagnetic eg
Cu2+ Fe3+ O2 CuO TiO VO2
Ferromagnetic eg
Fe Co Ni CrO2
Antifero eg
MnO
Ferrimagnetic eg
Fe3O4 MGFe2O4 ZnFe2O4
What becomes paramagnetic from ferrimagnetic at 850K
850K Fe3O4
Domain
A cluster of atoms in a ferromagnetic substance, all of which align in the same direction in the presence of an external magnetic field
band
atomic orbitals of metal atoms form molecular orbitals which are close in energy to each other as to form band
how many elements of symmentry are there in cubic
23
highest cation anion ratio
CsF
ionic crystal where max dis betw centers
CsI
