According to the information I have, you can get the file in three ways:
Send your sample for analysis after synthesis, they will give you the analysis file, use databases or use related software.
CIF files for many compounds can be downloaded from the American Mineralogist Crystal Structure Database (AMSD), or from the Crystallography Open Database (COD), for instance. A file in the CIF format may contain the positions of atoms, as well as the symmetry group that the compound belongs to.
If you can provide me with the lattice parameters or JCPDS card number, I can download the exact CIF file for you. Please let me know which one you have and I will be happy to assist you. Vembakam Vijayakanth