(1)A(1) reversible arrow T-5(2) spin transition in new thermochromic iron(II) complexes with 1,2,4-triazole and 4-amino-1,2,4-triazole

New complexes of iron(II) chloride and bromide with 1,2,4-triazole (Htrz) and 4-amino-1,2,4-triazole (NH(2)trz) of composition Fe(HtrZ)(3)Cl-2 . 1.5H(2)O, Fe(NH(2)trZ)(3)Cl-2 . 2H(2)O, Fe(Htrz)(3)Br-2 . 2H(2)O, and the Fe(NH(2)trz)(3)SO4 . H2O complex were synthesized and studied by magnetochemical, electronic, IR and Mossbauer spectroscopy methods. Magnetochemical studies showed that these complexes exhibit (1)A(1) reversible arrow T-5(2) spin transition accompanied by thermochromism (a reversible pink reversible arrow white change of color).