What is the formula name of CuNH4Cl2?

Answer 1

As gaseous ammonia with solid coppersulfate:

2NH3(g) + CuSO4(s) --> Cu(NH3)2SO4(s)

With water:

[Cu(NH3)2]2+ complex-ions with SO42- ions in aquous solution (deep blue color)

Answer 2

CuSO4 + NH3Cl --> CuCl2 + (NH4)2SO4

Answer 3

CuSO4 + 2NH4CL = CuCl2 + (NH4)2SO4