What is the explanation that in the amorphous silica appears a peak. If you have an amorphous material won't should appear any peak in the XRD pattern.?????
You have a broad peak in an amorphous material as there is some short range order - there is obviously a fixed distance between bonds in an amorphous material. For example water shows a broad band and the Si-O bond is around the same length in silicates. Crystalline materials with rigid long range order show sharp peaks at fixed Bragg angles.
Show your diffraction pattern please. A sharp peak indicates Bragg diffraction from a crystallite, broad 'peaks' are always present - this is the coherent scattering arising from non-random interatomic distances in the material.
See e.g:
Mozzi R & Warren B (1969) The structure of vitreous silica. J. Appl. Cryst. 2(4):164-172.
Wright AC (1990) Diffraction Studies of Glass Structure. J. Non-Cryst. Solids 123(1-3):129-148.
Mei Q, Benmore CJ, & Weber JKR (2007) Structure of liquid SiO2: A measurement by high-energy x-ray diffraction. Phys. Rev. Lett. 98(5).
Mei Q, Benmore CJ, Sen S, Sharma R, & Yarger JL (2008) Intermediate range order in vitreous silica from a partial structure factor analysis. Phys. Rev. B 78(14):144204.
It cud be impurities, sample holder or crystalline silica. All u need to do is to post ur data.
Alan Fawle is right. Amorphous materials give rise to broad peaks due to the presence of short range order. The peak height decreases rapidly with increasing 2theta.
- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Climate Science
- Climate Change