hello all!!!

in the solid state we have the 7lattices, right??? all of u must have devised some way to memorize it. i want to share my way.plz let me know whether u liked it or not. if u have some more methods do share with all !!!

 

the seven lattices are cubic, tetragonal, orthorombic, hexagonal, rhombohedral, monoclinic and triclinic. first, remeber this CT OH RMT. Keep this in ur mind and  u will be able to do it.

 

C-CUBIC

T-tetragonal

O-orthorombic

H-hexagonal,

R-rhombohedral

M-monoclinic

T-triclinic

 

NOW, THE NEXT STEP IS TO REMEMBER THE DIMENSIONS.

first we have,

a=b=c

a=bc

abc

a=bc

a=b=c

abc

ab c

 

 

can u notice a pattern? if not, i will tell u.

first all three are equal

 then we put unequal sign b/w b and c

 then all the three bcum unequal.

then again c is not equal to b.

then all three are equal agian 

 all three are unequal

all three are unequal.

( so basically there is a shift in no. of = and not equal to sign.)

 

LETS MOVE ON TO THE ANGLES.

a=b=y=90

a=b=y=90

a=b=y=90

a=b=90, y=120

a=b=y90

a=y=90, b 120

aby90

 

now here do u notice a pattern???

three times all the three angles are equal to each other and 90.

then we have a and b equal to each other and 90 but y is 120.

all the angles are eual to each other but not 90.

then now, a and y are equal to each other and 90 but b is NOT 120

then neither is equal to each other and 90..

 

EXAMPLES:

for cubic- take the first two letters of cubic u have Cu which is one example.u can remember NaCl as  it is salt and when salt comes into ur mind, u can associate it with sugar crystals which are sort of cubic in shape.

 

for tetragonal, remember white Tin and TiO₂    (T in both).

for orthorhombic, simple one rhombic sulphur and BaSO₄ ( Both compunds can be related by sulphur)

for hexagonal, we already know graphite and ZnO( ZnO can be remembered by that xa sound similar to za)

rhombohedral - other name for it is trigonal. tri means three. so we have CaCO₃

and relate that with cinnabar( C frm CaCO3 and Cinnabar).

then monoclinic is simple, we have monoclinic sulphur as one example and Na₂SO₄.10H₂O.

last but not the least we have triclinic. see TRI meaning 3. hence example IS H₃BO₃ .

 SO, IN SHORT.........

systems                axial angles       distances     examples

CUBIC                  a=b=y=90             a=b=c       Cu, NaCl

TETRAGONAL      a=b=y=90             a=bc       White Tin, TiO2

ORTHORHOMBIC  a=b=y=90             abc       Rhombic Sulphur BaSO₄

HEXAGONAL         a=b=90, y=120       a=bc        graphite and ZnO

RHOMBO

HEDRAL               a=b=ynot=90         a=b=c        CaCO₃,cinnabar                                                                                                                                                     .

MONOCLINIC       a=y=90, b 120  abc     monoclinic S                                     

TRICLINIC.             aby90               abc   H₃BO₃

 

hope u all found it useful. plz let me know.