Standard enthalpy of sublimation (ΔH°_sub )

It is the change in enthalpy that occurs when a mole of a solid element or a mole of a solid compound at the standard state is converted completely into a gas at its standard state.

Ca(s) → Ca(g)                        ΔH°_sub  = 193kJmol^-1

Standard enthalpy of evaporation (ΔH°_vap )

It is the change in enthalpy that takes place when a mole of a liquid compound or element at the standard state is converted into a mole of a gaseous compound/ element at its standard state.

Br2 (l) → Br2 (g)              ΔH°_vap      =30.91 kJmol^-1

Standard enthalpy of fusion (ΔH°_fus )

It is the change in enthalpy that takes place when a mole of a solid compound or element at the standard state is converted into a mole of liquid compound/element at standard state.

Al(s) → Al(l)                        ΔH°_fus=10.7 kJmol^-1

Standard enthalpy of atomization ( ΔH°_at )

It is the change in enthalpy that takes place when an element or a compound at the standard state is converted into a mole of gaseous atoms at the standard state.

½Cl2(g) → Cl(g)                    ΔH°_at= 121 kJmol^-1

Standard enthalpy of first ionization ( ΔH°_IE1 )

It is the change in enthalpy that takes place when a mole of gaseous uni-positive ions are formed by removing an electron from each atom that is most weakly bonded to the nucleus from a mole of gaseous atoms of an element at standard state.

Na(g) → Na⁺(g) + e                 ΔH°_IE1 =496 kJmol^-1

Standard enthalpy of electron affinity (or electron gain) (ΔH°_EA  )

It is the change in enthalpy that takes place when a mole of uni- negative ions are formed in the gaseous state when electrons are given to a mole of atom in the gaseous state under standard state.

Cl(g) + e → Cl¯(g)                        ΔH°_EA = -349  kJmol^-1

Standard lattice enthalpy of an ionic compound ( ΔH°_L  )

It is the change in enthalpy that takes place when one mole of an ionic compound in the solid state is formed from gaseous positive ionsand negative ions at the standard state.

Na⁺(g)+ Cl^– (g)→  NaCl(s)                   ΔH°_L =- 788 kJmol^-1

Born – Haber cycle

The thermochemical cycle that is developed to find the enthalpy change of lattice formation of an ionic compound is called the Born-Haber cycle.