Ammonium hexabromomercurate(II) is a chemical compound with the chemical formula .
Synthesis.
Heating of a mixture of mercury(II) bromide and ammonium bromide:
Physical properties.
The compound forms black crystals of tetragonal system, space group "P"4/"mnc", cell parameters: a = 0.925560 nm, c = 0.88657 nm, Z = 2.
At a temperature of 200 K, the compound enters a phase of the monoclinic system, space group "P"21/"n". At 250 K, it forms crystals of the orthorhombic system, space group "Pnnm".