Are you sure of the identification of SiO2? Is in the quartz form? It seems difficult that SiO2 could derive from the glass slide. Could you post your pattern?

Dear Umme Thahira Khatoon

Assalamu Alaikum

Ramadan Kareem

It is difficult (but it is impossible) to get SiO2 peaks in the case of using reagents free of Si - traces. As well as the using of glass slide to cover the beaker (when you heating the solution at 100 oC during synthesis of samples) has no effect.

Please re-check your samples again.

Please attach your XRD pattern.

Thank you

It is difficult to get this. So, attach the graph.

please find the patterns, correct me if I am wrong.

There are two more possibilities, albeit if you have gone through those steps: First, have you ground the initial powders in a agate mortar? Second, have used any quartz tube for sintering the products? In both cases, the SiO2 could have dispersed into your material. (Just guess due to experience)

From your pattern the phase it is not SiO2. It seems more plausible that it could be Cu3N

I'm agree with Dr. Bini. In addition, if we assume that it is SiO2, it should be a main phase  (the greatest intensity of "SiO2" reflection).. You can try to make a quantitative calculation for these data.

Dear Umme Thahira Khatoon

I concur with both Dr. Marcella Bini and Dr. Vadim S. Gorshkov. This peaks may be due to one probable copper nitrate CuN, copper oxide or any other copper phase.

Check your deposited sample by EDX or XPS techniques.

I hope for you all the best

Good luck

Hello,

 The main diffraction peak (110) is at 2theta = 30-31 degrees, and the (211) is at about 62 degrees, so the observed diffraction peaks cannot be indexed as SiO2 phase.

Since you have covered the beaker while  heating the solution at 100C, it may be a structure type likasite Cu3[NO3][OH]5[H2O]2 that have the main peak (210) at about 16 degrees and the second peak (200) at about 8.5 degrees in 2 Theta.

This structure may due to the reaction between the Cu, N and the vapor.