Chemistry

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Cubic Unit Cell Calculator.

Calculate crystal density from molar mass, cubic edge length, and formula units per cell.

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Set your values

Results update as you type.

Density: 2,163.624967 kg/m³

Density

2,163.624967kg/m³
Density: 2.163625 g/cm³

Density

2.163625g/cm³

How to Use

Every model convention and source-dependent parameter is visible. Results update automatically after each edit.

Use Cases

Determine density of crystalline solids

Use this calculator to find the density of a crystal when you know its molar mass, lattice parameter, and number of formula units per cell. Ideal for materials science and solid-state chemistry.

Example: For NaCl with molar mass 58.44 g/mol, edge length 5.64 Å, and 4 formula units per cell, density ≈ 2.16 g/cm³.

Verify experimental crystal data

Cross-check your X-ray diffraction results by calculating theoretical density and comparing with measured values. Helps identify impurities or structural defects.

Example: Compare calculated density of a metal with its measured density to assess purity.

Frequently Asked Questions

How do I calculate crystal density using this calculator?
Enter the molar mass of the substance, the cubic edge length (in appropriate units), and the number of formula units per unit cell. The calculator will compute the density using the formula: density = (molar mass * formula units) / (Avogadro's number * edge length^3).
What units should I use for the cubic edge length?
The calculator accepts edge length in common units like angstroms, nanometers, or picometers. Ensure you enter the value in the unit specified by the calculator's input fields. The result will be in grams per cubic centimeter (g/cm³) or as indicated.
What is a formula unit per cell?
A formula unit is the smallest repeating unit in a crystal lattice. For example, in NaCl, each unit cell contains 4 formula units. This number is essential for density calculation because it accounts for the number of atoms or ions in the cell.

Tips & Common Mistakes

Tips

  • Ensure the molar mass is in grams per mole (g/mol) for consistent density units.
  • Convert edge length to centimeters if you want density in g/cm³; the calculator may handle unit conversions automatically.
  • Double-check the number of formula units per cell for the specific crystal structure (e.g., FCC has 4, BCC has 2, SC has 1).
  • Use accurate Avogadro's number (6.022 × 10²³) for precise results.

Common Mistakes to Avoid

  • Forgetting to convert edge length to the same unit system as molar mass, leading to incorrect density.
  • Using the number of atoms instead of formula units for ionic compounds, which can double or halve the result.
  • Misidentifying the crystal structure and using the wrong number of formula units per cell.

Last updated: August 13, 2026