Abstract. Nickel(II) tetrafluoroborate is capable of forming a variety of complexes with 4-amino-1,2,4-triazole (NH 2 trz), as NH 2 trz can coordinate to one, two, or three Ni 2+ ions and thus can give rise in particular to polynuclear compounds of "infinite" dimensions. From rather concentrated solutions in the presence of an excess of Ni 2+ , however, crystallization of the trinuclear compound [Ni 3 (NH 2 trz) 6 (H 2 O) 6 ](BF 4 ) 6 · 4H 2 O is observed. In this complex, adjacent nickel ions are connected with three bridging NH 2 trz ligands, and three water molecules are bound to each of the terminal nickel atoms. The Ni-N distances at the central Ni 2+ ion were found to exceed those at the terminal Ni 2+ ions, in account with the trans influence of the involved ligands. The dis-