Crystal structure determining of 7-ADCA based on X-ray powder diffraction

Traditionally, crystal structure data can be collected and determined from single-crystal X-ray diffraction. However, in the fields of organic and macromolecular crystallography, it is often difficult or impractical to grow single crystals with suitable sizes and purity. Therefore, it will be benefited from the newly growing analytical tool that combining X-ray powder diffraction based on polycrystalline samples and ab initio calcula- tion[1]. 7-ADCA is one of the most important intermediate…

Crystal structure determining of 7-ADCA based on X-ray powder diffraction

Optimum resolution data of X-ray powder diffraction for 7-amino desacetoxy cephalosporanic acid(7-ADCA) were collected from an X′ Pert Pro MPD diffractometer with the setup of 0.01°/s and 0.01° per step. Indexing to the crystal system and searching space group from the diffraction data were conducted by means of the computational crystallography method. The pilot crystal models of 7-ADCA were then refined by Rietveld method to obtain the exact three-dimensional structure. The results show that the crystal structure of 7-ADCA is monoclinic, space group P2₁ with unit cell dimensions a=13.50 Å, b=6.01 Å, c =5.91 Å, α= γ =90.00°, β=101.96°, Z=2 and V = 469.10 ų. The fraction coordinate of each atom in the unit cell is well located and reported.