Go here

http://www.crystallography.net/index.php

Try this: http://rruff.geo.arizona.edu/AMS/amcsd.php 

 Thank you Sir for your suggestions. But I had gone through both the sites but I didn't find the actual (CIF)reference codes which I mentioned in the questions.

see an example of spinel

American Mineralogist 76 (1991) 1455-1458

A time-of-flight neutron powder diffraction study of MgAl2O4 at temperatures

up to 1273 K

sample W, T = 293 K

_database_code_amcsd 0001398

8.08435 8.08435 8.08435 90 90 90 *Fd3m

.125 .125 .125

atom x y z occ Biso

Mg .125 .125 .125 .68 .24

Al .125 .125 .125 .32 .24

Al .5 .5 .5 .84 .70

Mg .5 .5 .5 .16 .70

O .26148 .26148 .26148 .53

Download AMC data (View Text File)

Download CIF data (View Text File)

Download diffraction data (View Text File)

View JMOL 3-D Structure

Yes sir, those types of CIFs I got. But problem is regarding the mentioned CIF files,  for example Alite(42-0551). In case of JCPDS files, I got the experiment based files but in same reference I did not get the calculated files. In Experimental based Files, atomic positions are not given, so I can't do rietveld analysis. 

If I go to Google and type in - Alite CIF - I get this:

http://www.crystallography.net/cod/9016125.html

this will give you a cif file for alite with all the atomic coordinates that can be used for quantitative Rietveld analysis.

how hard is it to search the web?

I am not able to find the Cif File of C3A(Tricalcium Aluminate 3CaO. Al2O3, crystal Structure-Orthorhombic). Can anyone please help?

it is available in material studio how ever if u still did not find it i will send it to you 

Can anyone send the cif data for Cd4Sb3

Can anyone send the cif data for Ni-Cu mixed ferrite(Cu0.5Ni0.5Fe2O4)