The Formation of MgS & MgO Monomers and Dimers from Magnesium, Oxygen, and Sulfur Hydrides.

The reaction of SH + MgH is shown in this quantum chemical study to be an energetically downhill pathway leading to the astronomically known MgS molecule as well as H. Hence, the formation of MgS in the gas phase is now shown to be a possible contributor to this diatomic molecule's observed astronomical abundance. Similarly, MgO can form through a related process with OH + MgH, but the energy costs are higher, implying that MgH could be consumed in reactions with SH faster than those with OH. Hence, MgS may be more abundant than MgO as a result in line with current astronomical observations. Additionally, further additions of MgS/MgO can lead to the dimers of these molecules, indicating that the formation of nanoclusters is possible. These structures could be the building blocks for larger dust grains and mineral-based materials that populate protoplanetary disks and, ultimately, lead to rocky bodies.