Unit Cell Volume Calculator

Calculate the volume of a crystallographic unit cell for all seven crystal systems based on lattice parameters and angles.

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Calculation Parameters

Specify your stoichiometry inputs.

2.0 Å15.0 Å
2.0 Å15.0 Å
2.0 Å15.0 Å
30°150°
30°150°
30°150°

Calculated Result

Unit Cell Volume (V) 125.00 ų
In Cubic Centimeters 1.25e-22 cm³
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Expert Tip

One Ångström (Å) is 10⁻¹⁰ meters, meaning 1 ų equals exactly 10⁻²⁴ cubic centimeters (cm³).

How this Calculator Works

This calculator determines crystallographic unit cell volume using lattice side dimensions and angles. Select the crystal geometry system and adjust variables:

  • Crystal System: Determines the geometric rules and which axes/angles are independent.
  • Side a, b, c: Unit cell edge lengths in Ångströms (Å).
  • Angles α, β, γ: Inner unit cell angles in degrees (°).

The results are computed instantly and updated in the results panel on the right.

Formula & Methodology

Cubic: V = a³ Tetragonal: V = a² * c Orthorhombic: V = a * b * c Hexagonal: V = a² * c * sin(120°) Monoclinic: V = a * b * c * sin(β) Triclinic: V = a * b * c * √(1 - cos²α - cos²β - cos²γ + 2cosα*cosβ*cosγ)

Where:

  • V: Unit cell volume (ų).
  • a, b, c: Lattice parameters (edge lengths).
  • α, β, γ: Lattice angles.

Step-by-Step Calculation Example

To calculate the volume of a monoclinic unit cell manually, follow these steps:

  1. Identify the input parameters. For example:
    • Crystal System = Monoclinic
    • a = 5.0 Å, b = 5.0 Å, c = 6.0 Å
    • Beta Angle (β) = 95°
  2. Apply the formula:
    1. Convert angle to radians: β = 95 * (π / 180) ≈ 1.658 rad 2. Apply formula: V = a * b * c * sin(β) 3. Calculate V = 5.0 * 5.0 * 6.0 * sin(95°) = 150.0 * 0.9962 ≈ 149.43 ų
  3. Verify the calculated value which is updated instantly in the results panel on the right.

Frequently Asked Questions

What is the unit cell volume formula for a cubic system?

V = a³, where a is the cubic edge length.

What is the unit cell volume formula for a hexagonal system?

V = a² × c × sin(60°) = 0.866 × a² × c.

Why is unit cell volume important in materials science?

Unit cell volume combined with formula unit count (Z) allows precise determination of theoretical crystal density.

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