The name of HI as a binary compound is hydrogen iodide.
Hydrogen iodide is composed of two elements: hydrogen (H) and iodine (I). In binary compounds, the name typically takes the form of the cation (positive ion) first, followed by the anion (negative ion). Since hydrogen is a non-metal in this case, it is named first as ‘hydrogen’, and iodine is named as ‘iodide’. Therefore, we combine the two to correctly describe the compound as hydrogen iodide.