**Acknowledgements**

The chapter will remain incomplete without the mention of Dr. Vilas Shelke and the hour-long discussions regarding crystal structure and x-ray diffraction which sparked the interest and provided the motivation for detailed studies necessary for the completion of this work. Without availing the facilities and the healthy discussions with Dr. Mukhul Gupta, Dr. V Ganeshan, and Dr. D M Phase from UGC DAE CSR Indore and Prof. S P Sanyal from Barkatullah University Bhopal the work would have remained incomplete.
