It has been observed in matrix isolation and laser ablation experiments.

Solid InH3 is a three-dimensional network polymeric structure, where In atoms are connected by In-H-In bridging bonds, is suggested to account for the growth of broad infrared bands when samples of InH3 and InD3 produced on a solid hydrogen matrix are warmed.

[6] When heated above −90 °C, indium trihydride decomposes to produce indium–hydrogen alloy and elemental hydrogen.

As of 2013, the only known method of synthesising indium trihydride is the autopolymerisation of indane below −90 °C.

[9] 1:1 amine adducts are made by the reaction of Li+[InH4]− (lithium tetrahydridoindate(III)) with a trialkylammonium salt.