does anyone know about any alternative for this software
Go to Add/Remove manager, select "All available applications" and type "Molecular" in the search form. The search result will show you several options.
I don't know if the available options are good for what you need, because I never used such programs, but I guess is a good start.
PS: you might need to enable universe and multiverse in the software sources
Thanks for the reply lovinglinux.
I found XCrySDen is good ti view crystal structure.
Though I do not know how to create or draw a crystal structure.
I am not sure whether it is possible at all with XCrySDen.
If anyone know please reply.
You cannot create or draw molecule right in Xcrysden. It's just visualization software to view several format of crystal structure.
If you want to draw molecule go to package manager and search for chemical or chemistry you will find some tool to view and draw molecule
Another useful software that can give you ability to draw and also visualize crystal structure is VESTA. It support many file format. Find more detail at: http://www.geocities.jp/kmo_mma/crystal/en/vesta.html