 The crystal structure of this compound was only determined in 2007.Silver fulminate can be prepared in a similar way, but this salt is even more unstable than mercury fulminate; it can even explode under water and is impossible to accumulate in large amounts because it detonates under its own weight.The thermal decomposition of mercury(II) fulminate can begin at temperatures as low as 100 °C, though it proceeds at a much higher rate with increasing temperature.