Mercury(II) hydride (systematically named mercurane(2) and dihydridomercury) is an inorganic compound with the chemical formula HgH2 (also written as [HgH2]).

[3] Alireza Shayesteh et al conjectured that bacteria containing the flavoprotein mercuric reductase, such as Escherichia coli, can in theory reduce soluble mercury compounds to volatile HgH2, which should have a transient existence in nature.

[3] The initial yield is high; however, due to the product being in an excited state, a significant amount dissociates rapidly into mercury(I) hydride, then back into the initial reagents: This is the preferred method for matrix isolation research.

In 1993 Legay-Sommaire announced HgH2 production in cryogenic argon and krypton matrices with a KrF laser.

[1] In 2004, solid HgH2 was definitively synthesized and consequentially analysed, by Xuefeng Wang and Lester Andrews, by direct matrix isolation reaction of excited mercury with molecular hydrogen.

[4] In 2005, gaseous HgH2 was synthesized by Alireza Shayesteh et al, by the direct gas-phase reaction of excited mercury with molecular hydrogen at standard temperature;[5] and Xuefeng Wang and Lester Andrews[4] determined the structure of solid mercury HgH2, to be a molecular solid.