定义
结晶学中的结构确定是指在有序晶格中详细描述散射中心的三维位置坐标（通常还有三维各向异性位移参数）的过程。当晶体由分子化合物组成时，该术语通常包括存在的每个分子化合物的化学结构的三维描述。
实验技术
由于原子在晶格中高度有序地排列成散射中心，大多数结构测定技术都涉及波长与原子尺寸相当的电磁波或物质波的衍射。布拉格定律规定了平面波从晶格平面衍射的条件。通过晶体的衍射辐射的强度随散射角的变化而变化。这种变化源于与晶格中存在的不同原子相关的平面上散射光束的构造性干涉和破坏性干涉。成像探测器可以将结果视为衍射点或衍射环的图案。
基于衍射的技术包括：
X射线衍射（单晶、纤维、粉末）
中子衍射（单晶、粉末）
电子衍射（选区、会聚束、进动）
γ射线衍射
与衍射法互补的其他三维结构测定技术包括
透射电子显微镜
核磁共振光谱（主要用于溶液中的生物大分子）
Definition
Structure determination in crystallography refers to the process of elaborating the three-dimensional positional coordinates (and also, usually, the three-dimensional anisotropic displacement parameters) of the scattering centres in an ordered crystal lattice. Where a crystal is composed of a molecular compound, the term generally includes the three-dimensional description of the chemical structures of each molecular compound present.
Experimental techniques
Owing to the highly ordered arrangement of atoms as scattering centres in a crystal lattice, most structure determination techniques involve the diffraction of electromagnetic or matter waves of wavelengths comparable to atomic dimensions. Bragg's law specifies the condition for plane waves to be diffracted from lattice planes. The diffracted radiation passing through a crystal emerges with intensity varying as a function of scattering angle. This variation arises from constructive and destructive interference of scattered beams from the planes associated with the different atoms present in the lattice. The result is seen by an imaging detector as a pattern of diffraction spots or rings.
Among diffraction-based techniques are:
X-ray diffraction (single-crystal, fibre, powder)
neutron diffraction (single-crystal, powder)
electron diffraction (Selected Area, Convergent Beam, Precession)
gamma-ray diffraction
Other techniques for three-dimensional structure determination that are complementary to diffraction methods include
transmission electron microscopy
nuclear magnetic resonance spectroscopy (used largely for biological macromolecules in solution)
