Bonding structure of H₃⁺, H₃ and H₃^-

Abstract

H₃⁺, H₃ and H₃^- are the simplest homo nucleus three atomic molecules and examples of three center two/three/four electron bond respectively. The structure of H₃⁺ takes the equilateral triangle that three H atomic nuclei become equivalent, because two electrons of H₃⁺ occupy the first node-less σorbital. In the case of H₃ and H₃^-, an electron (or two electrons) occupies the second σorbital which has a node through an H atom and a center of H-H bond of the equilateral triangle of H₃⁺. Thus, the structures of H₃ and H₃^- become linear. In this note, we show the angular dependence of molecular structure, orbital energy, total energy and Mulliken charge of H₃⁺, H₃ and H₃^- using HF/6-311++G**.