X-ray diffraction is a technique that uses the scattering of X-rays by the regularly arranged atoms in a crystal to measure internuclear distances in molecules and solids. From the diffraction pattern, the positions of the atoms and the spacing between them can be deduced. It is a principal method for determining bond lengths and the structures of crystalline substances.

X 射线衍射是利用晶体中规则排列的原子对 X 射线的散射来测量分子和固体中核间距离的技术。由衍射图样可推断原子的位置及其间距。它是测定键长和晶态物质结构的主要方法之一。