Effect of deuteration on hydrogen bonding in Glycine silver nitrate (GSN): a new isotopic polymorph

General: Ferroelectricity in GSN was discovered in 1957 by Pepinsky . This crystal undergoes a displacive type of structural phase transition with a very small transition entropy with curie temperature (TC) to be 218 K. Partial deuteration is found to raise the transition temperature by 15 K. Our Crystallization of the completely deuterated glycine silver nitrate (DGSN) gave a new polymorph with the crystal structure significantly differing from that of the nondeuterated form (GSN). we have also grown partially deuterated GSN (C deuterated, and N deuterated). Our initial characterization shows that the C-Deuterated is similar to DGSN and N deutuerated is similar to GSN. GSN is a light-sensitive crystal. Single-crystal X-ray diffraction investigations are difficult to perform on these crystals due to the problem of crystal deterioration on prolonged exposure to X rays. A way to circumvent the problem of the crystal deterioration on light exposure is to perform a neutron diffraction experiment in cryostat, and neutron diffraction is also a fundamental tool to study the effect of deuteration on the structural changes on the crystals particularly in this case, where the hydrogen bonding interaction seems to play a very important role in the stabilization of the various polymorphs.