Enter your Crystal System, Peak Position (2θ), X-ray Wavelength, Miller Indices (h, k, l), and Order of Reflection (n) into the Lattice Parameter Calculator to find your material's Lattice Constant (a), along with d-spacing, Bragg Angle (θ), and Q Value — optionally throw in Atomic Radius for extra context.
Lattice Constant (a)
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d-spacing
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Bragg Angle (θ)
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Q Value
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A lattice parameter is the physical dimension of unit cells in a crystal lattice. It defines the size and shape of the repeating unit in a crystal structure, typically measured in Angstroms (Å).
Use Bragg's law (nλ = 2d sinθ) to first calculate d-spacing from the peak position. Then apply the appropriate formula based on crystal system and Miller indices to determine the lattice constant.
The standard wavelength for Cu Kα radiation is 1.5418 Å, which is the default value in most XRD calculations. This is the most commonly used X-ray source in diffractometers.
Miller indices (h, k, l) are three integers that define the orientation of crystal planes. They are essential for calculating lattice parameters as different planes give different d-spacing values.
Choose based on your material's symmetry: cubic for simple metals, hexagonal for materials like graphite or zinc, tetragonal for materials like tin, and orthorhombic for more complex structures.
2θ is the diffraction angle measured in XRD experiments, while θ is the Bragg angle (half of 2θ). Most XRD software reports 2θ values, which is what you should enter in the calculator.
Accuracy depends on peak position precision, wavelength calibration, and sample quality. Typical accuracy is ±0.001 Å for well-defined peaks with proper instrument calibration.