Try to use the XRD refinement method like GSAS and include possible secondary phase along with the desire phase in the refinement. You can also use spectroscopic methods such as Raman, infrared, and UV-visible spectroscopy in which the allowed vibrational modes for the sample might be less in number compared to tits XRD peaks. So, identifying different phases in the sample might b easier using these spectroscopic technique.

Dear Shawn Devaraj

The first step for the analysis of the powder diffraction pattern is a search in a PDF-5 or COD database. It can use Qualx2 (free for academia, https://www.ba.ic.cnr.it/softwareic/qualx/) or the same PDF-5 software (https://www.icdd.com/pdf-5/) as interface.

It is also possible to look up the CIFs files of the expected material, and compare graphically the powder patterns calculated. In some cases it will see some displacement, with more or less the same distribution of intensities and positions of the maxima. The trick is to find the "correct" cell parameters and the "correct" zero or sample dispacement so that refinement proceeds properly. Also, extra maxima may appear, associated with a second phase.

In case there is no coincidence of any reported phase, then indexing starts to proceed.

Best regards

Analio Dugarte

First, you should perform a search of phases with one of the software that you can find in internet, connected to a crystallographic database. Your sample could in fact contain also traces of reagents, oxides or impurity phases. The indexing is not suitable in your case, you don't have a new phase. This is also a difficult process, particularly onto XRD powder data obtained with a laboratory diffractometer