Lattice Energy Calculator
Calculate lattice energy of ionic compounds using Kapustinskii, Born-Landé, and Hard-sphere equations
Calculate Lattice Energy
Sodium: +1, 102 pm
Chloride: -1, 181 pm
Examples: NaCl, MgO, CaO
Lattice Energy Results
Method: Kapustinskii equation
Formula: NaCl
Ion Charges: Na+ (+1), Cl- (-1)
Stability: Moderately stable ionic solid
Description: Moderate ionic bonding strength, typical for many salts
Example Ionic Compounds
Sodium Chloride (NaCl)
Common table salt
Experimental: 786 kJ/mol
Magnesium Oxide (MgO)
High melting point ceramic
Experimental: 3791 kJ/mol
Calcium Fluoride (CaF₂)
Fluorite mineral structure
Experimental: 2651 kJ/mol
Cesium Chloride (CsCl)
Different structure than NaCl
Experimental: 657 kJ/mol
Lithium Fluoride (LiF)
Small ion, high lattice energy
Experimental: 1037 kJ/mol
Lattice Energy Scale
< 500 kJ/mol
Low Energy
Large ions, low charges
500 - 1500 kJ/mol
Moderate Energy
Typical ionic salts
1500 - 3000 kJ/mol
High Energy
Small ions, higher charges
> 3000 kJ/mol
Very High Energy
Very small, highly charged ions
Calculation Methods
Common Structures
Understanding Lattice Energy
What is Lattice Energy?
Lattice energy is the energy required to completely dissociate one mole of an ionic solid into gaseous ions. It represents the strength of ionic bonding in a crystal lattice and is a measure of the electrostatic attraction between oppositely charged ions.
Key Factors
- •Ion Charges: Higher charges lead to stronger attraction
- •Ion Sizes: Smaller ions can get closer together
- •Crystal Structure: Different packing affects energy
Calculation Methods
Kapustinskii Equation
U = K × v × |z₊| × |z₋| / (r₊ + r₋) × (1 - d/(r₊ + r₋))
Most practical for general use
Born-Landé Equation
U = Nₐ × z₊ × z₋ × e² × M / (4πε₀ × r₀) × (1 - 1/n)
Includes repulsion correction
Born-Haber Cycle
Experimental thermodynamic approach using enthalpy data
Applications and Importance
Material Properties
Predicts melting points, hardness, and solubility of ionic compounds.
Crystal Engineering
Design of new materials with desired properties for technology applications.
Chemical Stability
Understanding formation and decomposition of ionic compounds.
Lattice Energy Trends
Charge Effect
Lattice energy increases dramatically with ion charge:
- • NaCl (1+, 1-): ~786 kJ/mol
- • CaO (2+, 2-): ~3791 kJ/mol
- • Al₂O₃ (3+, 2-): ~15,916 kJ/mol
Size Effect
Lattice energy decreases with increasing ion size:
- • LiF: ~1037 kJ/mol (small ions)
- • NaCl: ~786 kJ/mol (medium ions)
- • CsI: ~604 kJ/mol (large ions)