Unfortunately, the equation you submitted is incorrect, as there are no compounds with the formulas Hg₃Ni₂, Hg₂Ni₂ or Ni₂. Therefore, we are unable to provide detailed information, reaction conditions and processes, as well as the phenomena that occur.

Essentially, a chemical equation is a description of the transformation of substances into new products. Reaction conditions may include temperature, pressure, and depend on the specific reaction mechanism. The reaction process usually involves the decomposition or combination of molecules to form new products.

We apologize for the inconvenience. If you have another chemical equation, please submit it and we will provide the information you need.

Unfortunately, the chemical equation you provided is invalid and does not adhere to the law of conservation of atoms. Mercury (Hg) and Nickel (Ni) are two chemical elements that do not combine to form the compound Hg₃Ni₂ or Hg₂Ni₂. Also, Ni₂ or O₂ (oxygen gas) cannot be produced from the decomposition of this non-existent compound.

Please review your information or provide a valid and accurate chemical equation.