Regrettably, there may be a misunderstanding here. Hg2Ni2 is not the correct chemical formula for any compound. Hg and Ni are the chemical symbols for mercury and nickel respectively.
Mercury (Hg) is a silvery-white liquid at room temperature, with an atomic mass of about 200.59. It belongs to group 12 of the periodic table and is a heavy metal, which can be toxic if not handled carefully.
Nickel (Ni), a chemical element belonging to group 10 of the periodic table, is a silvery-white metal with an atomic mass of about 58.69. It can form a variety of compounds with other elements.
For a chemical compound to exist, the molecular structure and bonds between elements must follow chemical rules and atomic structure. But “Hg2Ni2” is not a correct chemical formula for any actual compound.