I'm not sure if I got your question right, but you will probably need a crystallographic information file (.cif) of those compounds, and import them into the software. Have you got them? Or is the problem elsewhere?

Hello Michal (Witam Michale ;-)) I know that there is a database on http://www.crystallography.net, but unfortunatelly there are no compounds which I'm looking for. Also my skills to create such models are weak.

I'm not an expert in perovskites, but maybe you could find .cif files of isostructural compounds and then manually alter atom assignments in the software. Maybe someone will be of more help here and suggest something more rational.

Now, do you know the atomic coordinates in these compounds, or can you at least, let's say, draw it on paper? If so, you can create the structure manually in Crystal Maker, by selecting file->new crystal, then insert the desired atoms, their occupancies and fractional coordinates...

You need .CIF file for your parental compounds for example....

YCrO3 compounds... It will available in ICSD database CDs...

Or get the structural details from the literature paper like a, b, c and co-ordinates of the individual atoms.... then you can fill it in crystal maker....

Double click crystal maker and then go to file and later on click on new crystal..

a window will apear where you can add all the details of it...

Y0.8Ca0.2CrO3

for addition of Ca you can change the site occupancy of 'Y' atom to 0.8

use the same co-ordinates and insert the Ca atom with site occupancy of 0.2

similarly you can make the other models

Above one is good...

You can open above file in crystal maker and edit structure from edit button

I would like to thank all of You. There are a lot of usefull information!

I will try to show off in near future, the results of my work.

I don't have (yet) datas from XRD, but I found here some informations: http://www.sciencedirect.com/science/article/pii/S0167273811001044. Everything is clear to this moment "...a fractional x coordinate for the site. Repeat for the y and z coordinates." Where I can get these?

OK, now I see ;-) thank You very, very much!