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Updated: Dec 26, 2025
Author Spotlight: A Rapid, Microwave-Assisted Hydrothermal Synthesis Of Nickel Hydroxide Nanosheets
Published on: August 18, 2023
Crystal structure of a nickel compound comprising two nickel(II) complexes with different ligand environments:
Karilys González Nieves1, Dalice M Piñero Cruz2
1Department of Natural Sciences, University of Puerto Rico, Carolina Campus, 2100 Avenida Sur, Carolina, PR 00987, Puerto Rico.
Abstract:
The title compound, di-aqua-[tris-(2-amino-eth-yl)amine]-nickel(II) hexa-aqua-nickel(II) bis-(sulfate), [Ni(C6H18N4)(H2O)2][Ni(H2O)6](SO4)2 or [Ni(tren)(H2O)2][Ni(H2O)6](SO4)2, consists of two octa-hedral nickel complexes within the same unit cell. These metal complexes are formed from the reaction of [Ni(H2O)6](SO4) and the ligand tris-(2-amino-eth-yl)amine (tren). The crystals of the title compound are purple, different from those of the starting complex [Ni(H2O)6](SO4), which are turquoise. The reaction was performed both in a 1:1 and 1:2 metal-ligand molar ratio, always yielding the co-precipitation of the two types of crystals. The asymmetric unit of the title compound, which crystallizes in the space group Pnma, consists of two half NiII complexes and a sulfate counter-anion. The mononuclear cationic complex [Ni(tren)(H2O)2]2+ comprises an Ni ion, the tren ligand and two water mol-ecules, while the mononuclear complex [Ni(H2O)6]2+ consists of another Ni ion surrounded by six coordinated water mol-ecules. The [Ni(tren)(H2O)2] and [Ni(H2O)6] subunits are connected to the SO4 2- counter-anions through hydrogen bonding, thus consolidating the crystal structure.
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