Structures and stability of LB⋅E13H2E14H2E15H2⋅LA compounds, stabilized by Lewis base (LB) and/or Lewis acid (LA), were computationally explored. Obtained results reveal that the isomers with the middle position of group 14 element are the most stable for all studied combinations of group 13-14-15 elements (B, Al, Ga; Si, Ge, Sn; P, As, Sb). Coordination of LA lowers the energy difference between isomers but increases the activation energy for the isomerization. Stronger LB, such as NHC, also increase the activation energy for the isomerization. Possible synthetic approaches to the main group hydride isomers with the middle position of group 14 element were proposed and computationally examined.