Identification of structures and crystal forms of a compound (comparison to a database)

Identifying crystalline structures and forms is an essential step in characterizing solid materials , whether they are of polymeric, mineral, pharmaceutical, or food origin. Performed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) , this analysis allows the determination of the crystallographic nature , purity , polymorphic phase , and structural conformity of a compound by comparing it to reference databases.

This study is essential in the fields of materials and polymers , packaging , pharmaceuticals , as well as for quality control and regulatory compliance research .

Principles and objectives of crystal analysis

Each compound possesses a specific atomic organization that determines its physical properties (solubility, hardness, melting point, stability, etc.). XRD and FTIR methods allow this internal organization to be revealed and precisely identified.

The analysis aims to:

• Identify the crystalline or amorphous phases of a pure material or compound;
• Compare a sample to a crystallographic database (ICDD, COD, etc.) to confirm its identity;
• Determine the purity and proportion of mixed phases (e.g., polymorphic or solvate);
• Detect structural changes related to a manufacturing process, thermal exposure or aging;
• Evaluate the conformity of an ingredient or finished product with its technical specifications.

This characterization is particularly useful for validating the reproducibility of processes and ensuring the consistency of material performance.

Analytical methods used

• X-ray diffraction (XRD) : the reference method for studying crystal structure. An X-ray beam is directed at the sample and diffracted at an angle specific to each structure. The diffraction pattern is then compared to international databases to identify the crystalline phase. This
  method provides the crystallographic profile of a material;
  it offers information on crystallite size , overall crystallinity , and the phases present ;
  it is non-destructive and applicable to powders, films, fibers, and bulk materials.

• FTIR (Fourier Transform Infrared) spectroscopy : complementary to XRD, it allows the identification of functional groups and the distinction between polymorphic and amorphous forms.

  Ideal for confirming the presence of specific bonds;
  Can be used on solid, liquid or semi-solid samples;
  Associated with a spectral database for structural validation.

or Raman NMR analyses can be incorporated to refine the interpretation and confirm the molecular structure.

Industrial applications

The identification of crystalline forms is relevant to many sectors:

• Materials and polymers : study of crystallinity rates, control of semi-crystalline structures, identification of polymorphs in engineering plastics (PE, PP, PET, etc.);
• Packaging : verification of the structural stability of barrier layers and compatibility of multilayer materials;
• Pharmaceutical and nutraceutical : control of polymorphs of active ingredients (alpha, beta, amorphous forms), guaranteeing the bioavailability and stability of the product;
• Cosmetics and fine chemicals : identification of crystalline phases in powders, pigments or excipients;
• R&D and innovation : highlighting new crystalline structures resulting from synthesis or crystallization processes.

Technical characteristics and interpretation of results

The analyses are performed according to the international standards ISO 21414 (XRD) and ISO 10640 (FTIR), guaranteeing the reliability of the results and comparability with global databases.
The results include:

• Diffraction diagrams ( 2θ, relative intensity);
• Infrared spectra with assignment of characteristic bands;
• Correlation reports with crystallographic databases;
• An expert interpretation of the identified phases and their significance for the stability or conformity of the material.

All tests are carried out by ISO 17025 accredited , ensuring traceability and analytical rigor required for industrial and regulatory applications.

YesWeLab Expertise and Support

YesWeLab provides access to its network of specialized structural and crystallographic analysis , capable of combining XRD, FTIR, Raman, and NMR approaches.
Our scientific team assists you in selecting the method best suited to your material (powder, polymer, crystalline, amorphous) and your objectives (identification, purity, conformity, or failure detection).

Thanks to the YesWeLab digital platform , managing your analyses is simplified: requesting quotes, sending samples, real-time tracking and receiving results online.

Further analyses recommended

For a complete characterization of your materials, YesWeLab also recommends:

• FTIR Infrared Spectroscopy
• Raman spectroscopy
• Scanning electron microscopy (SEM)

These combined analyses provide a comprehensive view of the structure, composition, and thermal behavior of organic and polymeric materials.