Lattice Energy Calculator
Use this Lattice Energy Calculator to work through the same calculation as the main calculator page with clear steps, examples, and result context.
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Run the calculator.
What This Lattice Energy Calculator Helps You Do
This page turns the basic electrostatic picture of ionic solids into a direct calculator, which is the fastest way to compare how charge and ion separation affect lattice energy.
The result is most useful as a trend and comparison tool, especially when checking why some ionic compounds bind more strongly than others.
How to Calculate Lattice Energy Calculator
- Enter ionic charges: Provide the magnitude of the cation and anion charges for the ionic compound.
- Enter ion separation: Use the interionic distance or nearest-neighbor separation in picometers.
- Estimate lattice-energy trend: The calculator scales energy with charge product divided by separation and reports a chemistry-friendly kJ/mol estimate.
- Interpret the trend: Larger charge product and smaller distance mean a stronger ionic lattice and higher lattice-energy magnitude.
Lattice Energy Calculator Formula
| Variable | Meaning | Unit |
|---|---|---|
| q1, q2 | Charges of the cation and anion | elementary-charge multiples |
| r | Interionic distance | pm or nm |
| U | Estimated lattice energy magnitude | kJ/mol |
Use the worked examples below to check how the formula behaves with real values. If the result looks unexpected, verify the unit assumptions and the meaning of each variable before interpreting the answer.
Worked Examples
- Cation charge: +1
- Anion charge: -1
- Distance: 281 pm
Result: Estimated lattice-energy magnitude is moderate.
A 1:1 ionic compound with a relatively large separation has a smaller lattice-energy magnitude than highly charged salts.
- Cation charge: +2
- Anion charge: -2
- Distance: 240 pm
Result: Estimated lattice-energy magnitude is much larger than NaCl.
Higher ionic charges dominate the lattice-energy comparison.
- Case 1: 1 and 1
- Case 2: 2 and 2
- Distance: 250 pm
Result: The 2/2 case has roughly four times the electrostatic strength term.
Charge product has a strong effect because it multiplies directly in the energy model.
- Charges: 1 and 1
- Distance 1: 300 pm
- Distance 2: 200 pm
Result: The shorter-distance case has the larger lattice-energy magnitude.
Pulling ions closer together strengthens the attraction.
How to Interpret Your Results
| Range | Meaning | Action |
|---|---|---|
| Low charge product or long distance | Lower lattice-energy magnitude. | Expect weaker electrostatic binding relative to compact, highly charged salts. |
| Moderate charge product and distance | Typical ionic-crystal attraction. | Use the result for trend comparison rather than exact crystal-structure prediction. |
| High charge product and short distance | Very strong ionic lattice attraction. | Expect large lattice-energy magnitude and strong crystal binding. |
Frequently Asked Questions
References
Last reviewed: March 2026