The Ewald construction

How the Ewald sphere is built and why it tells which reflections are observed. Follow the steps, in 2D (a plane of the reciprocal lattice and the Ewald circle) or in 3D.

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hkl labels

2D shows the h0l plane of the reciprocal lattice, which contains the beam. Drag to pan, scroll to zoom, click a point to select it.

Beam and crystal rotation

λ (Å) 1.54 ω (°) 0.0° Speed 10°/s

ω rotates the crystal, and so its reciprocal lattice, about a vertical axis through the origin O. At ω = 0, c* is along the beam.

Crystal system Bravais lattice

Lattice parameters

a (Å)

b (Å)

c (Å)

α (°)

β (°)

γ (°)

Range (h, k, l): min, max

h k l

Only lattice-centring extinctions are applied (no glide planes or screw axes).