X-ray diffraction XRD is a powerful analytical technique used to determine the crystal structure and composition of unknown inorganic samples. It works by exposing the sample to a monochromatic X-ray beam, which interacts with the atoms in the crystal lattice, causing the X-rays to scatter in different directions. The scattered X-rays form a diffraction pattern, which can be analyzed to reveal information about the crystal structure and composition of the sample.Here's a step-by-step process of how XRD can be used to determine the exact composition and crystal structure of an unknown inorganic sample:1. Prepare the sample: The unknown inorganic sample is ground into a fine powder to ensure a random orientation of the crystals. This increases the likelihood of obtaining a complete diffraction pattern.2. X-ray exposure: The powdered sample is placed in an X-ray diffractometer, where it is exposed to a monochromatic X-ray beam. The X-rays interact with the electrons in the crystal lattice, causing them to scatter in various directions.3. Collect diffraction pattern: The scattered X-rays form a diffraction pattern, which is detected by a detector e.g., a photographic film or a digital detector . The diffraction pattern consists of a series of spots or rings, each corresponding to a specific set of lattice planes in the crystal structure.4. Analyze diffraction pattern: The diffraction pattern is analyzed using Bragg's Law n = 2d sin , which relates the wavelength of the X-rays , the angle of diffraction , and the distance between the lattice planes d . By measuring the angles and intensities of the diffraction peaks, the crystal structure and unit cell parameters can be determined.5. Identify the composition: The obtained crystal structure and unit cell parameters are compared with known structures in crystallographic databases e.g., the Inorganic Crystal Structure Database or the Crystallography Open Database . A match indicates the identity of the unknown sample.There are several factors that can affect the accuracy of XRD analysis:1. Sample preparation: The quality of the sample preparation, such as the particle size and homogeneity, can significantly impact the accuracy of the analysis. Poorly prepared samples may result in weak or incomplete diffraction patterns.2. Instrumentation: The quality and calibration of the X-ray diffractometer, including the X-ray source, monochromator, and detector, can affect the accuracy of the analysis. Proper maintenance and calibration of the instrument are essential for obtaining accurate results.3. Data analysis: Errors in data analysis, such as incorrect peak identification or background subtraction, can lead to inaccurate determination of the crystal structure and composition.4. Sample complexity: The presence of multiple phases, impurities, or amorphous components in the sample can complicate the analysis and make it more challenging to accurately determine the crystal structure and composition.5. Temperature and pressure: The crystal structure and composition of some materials can be affected by temperature and pressure. Therefore, it is essential to perform the XRD analysis under the appropriate conditions to obtain accurate results.