Z = Effective nuclear charge; Z = Atomic Number ; σ = Shielding

λ = Radioactive Decay Constant or Disintegration Constant; t = Time interval for which radioelement is present ;  

n₀ = Initial number of atoms ; n= Final number of atoms.

t_1/2 = Half Life of Radioactive elment; λ = Decay Constant of the radioactive element

t_1/2 = Half-life of the isotope; T = Time taken for the specific decay ; W_ini = Initial amount of the radioactive isotope; W_fin = Final amount of the radioactive isotope

d= Interplanar Spacing ; h , k , l = Miller Indices; a ,c = Lattice Constants

d_hkl= Lattice Spacing ; a = Lattice Constant ; h , k , l = Miller Indices;

n = An integer ;   λ = Wavelength of the incident light ; d_hkl= Lattice Spacing ; θ = Angle of incidence ; 

U=Lattice Energy ; N_A= Avogadro Number ; M= Madelung Constant ; z⁺ & z^- = Charge on the Cation & the Anion;

e = Change of an electron; n= Born Exponent ; r =Inter ionicDistance; ε_o = Permitivity of free Space; 

Q= Amount of Heat ; m= mass ; s = Specific Heat ; θ = Temperature Change (a.k.a ΔT)