Study On The Microscopic Behaviors Of Hydrogen Bonding

Hydrogen bond is the most important intermolecular bonding interaction in inorganic crystals.It's a very active research field in crystal engineering, solid-state chemistry and solid-state physics.Hydrogen bonds are flexible and complicated, which do not fit perfectly into traditional models of chemistry. Most cations tend to be found in regular coordination sphere, but hydrogen ion in inorganic crystals is usually found strongly displaced from the center of its coordination environment. Hence, the nature of hydrogen bond is often the hot subject of investigations and polemics.Based on the structural data of X-H…Y hydrogen bonds (X=N, O;Y=N,O) extracted from Inorganic Crystal Structure Database, this dissertation establishes the stretching model of hydrogen bonds by using the chemical bond method, which reveals the nature of X-H…Y hydrogen bonds in inorganic crystals.In the process of X-H…Y hydrogen bond formation, X-H bond and H…Y bond are stretched from their original bond lengths, which change along with the chemical environments of X and Y, to their experimental bond lengths respectively. After establishing a new method to calculate bond valence,the bond valence-bond length correlations of X-H bond and H…Y bond are described more perfectly by using the obtained new bond valence parameters.The atomic electronegativity of H is calculated to be 1.63 through establishing a new atomic electronegativity scale of main block elements.While forming chemical bonds with X or Y, H display effective electronegativitis, which reflect the abilities of chemical bonds formation. The covalencies of X-H bond and H…Y bond both increase with bonds shortening, and their ionicities decrease,namely the covalent interactions strengthen and the electrostatic interactions weaken. The atomic electronegativity and bond valence are the most important factors in determining hydrogen bond properties. For both furcated and not furcated hydrogen bonds, the properties of X-H bond and H…Y bond can be characterized by their correspondingχXχHS andχYχHs,such as bond stretching frequency and bond energy. The forces exerted on H by X-H bond and H…Y bond obey the rule of force balance, thus this stretching model can predict the structures of X-H…Y hydrogen bonds in inorganic crystals.Next the hydrogen bond structure-material properties relationships are need to formulate, then a design route is suggested to adjust hydrogen bond structure and further control the properties of inorganic crystal material. This provides theoretical guidance for optimizing crystal structure and designing novel functional material.