Geometric and Electronic Structure Evolution of Gallium Hydrides: Group 13 Perspective

This article systematically investigates the structural evolution of gallium (Ga) hydrides using a combination of density functional theory and ab initio calculations. The global minimum energy structures are determined for each cluster in the Ga₂H_x (x = 0-6) and Ga₃H_y (y = 0-9) series. The chemical bonding characteristics are analyzed through orbital- and electron-density-based methods, providing insights into the properties of Ga hydrides within the broader context of Group 13 hydrides. The examined Ga hydride clusters exhibit structural and electronic similarities to their aluminum (Al) counterparts, positioning them as a bridge between the lighter boron (B) hydrides and the heavier indium (In) and thallium (Tl) hydrides. While B hydrides tend to share electrons through two-center and three-center bonding, the heavier congeners often retain unpaired electrons or lone pairs and exhibit thermodynamic instability toward dehydrogenation of their saturated hydrides.