Two new one-dimensional chain complexes, (NH4)2[Cu(NH3)2(CrO4)2](1) and (NH4)2·[Ni(NH3)2(CrO4)2](2), were obtained by mixing copper nitrate or nickel nitrate with the same molar of ammonium dichromate in ammonia water at room temperature, and they were characterized by single-crystal X-ray diffraction(XRD), thermogravimetric analysis(TGA) and differential thermal analysis(DTA). Furthermore, the complexes were magnetically characterized by temperature-dependent magnetic susceptibility, field-dependent magnetization, and alternate current(AC) magnetic measurements. The structure analysis results show that crystals of both complexes are triclinic, space group P1 with a=0.59090(12) nm, b=0.6929(3) nm, c=0.73740(15) nm, α=107.03(4)°, β=92.79(3)°, γ=112.44(2)° for Cu(Ⅱ) complex and a=0.56987(7) nm, b=0.69972(9) nm, c=0.73335(8) nm, α=104.929(3)°, β=96.7121(3)°, γ=112.325(4)° for Ni(Ⅱ) complex. In the crystal structure, the [M(NH3)2]2+ units are linked by two chromato bridges, forming an eight-member ring. As a whole, both complexes have one-dimensional chain structures. The two complexes began to break down as the temperature gradually reached 150 ℃ or so, leaving behind H2Cr2CuO5 and H2Cr2NiO5, and afterwards they are dehydrated at above 410 ℃. The temperature-dependent magnetic susceptibilities were measured in the range of 2—300 K, which implies a weak antiferromagnetic interaction between the adjacent mental ions. The field-dependent magnetization and AC magnetic measurements indicate that the two complexes are both antiferromagnets.
