title: Crystal structure of hexa-aqua-nickel(II) bis{2-[(5,6-di-hy-droxy-3-sul-fon-ato-quino-lin-1-ium-7-yl)oxy]acetate} dihydrate.
abstract: The asymmetric unit of the title compound, [Ni(H2O)6](C11H8NO8S)2·2H2O, features a half-hexa-aqua-nickel(II) complex cation with the Ni(II) ion on an inversion center, one deprotonated 5,6-dihy-droxy-3-sulfoquinolin-7-yloxyacetic acid (QOH) molecule appearing in its zwitterionic form and one lattice water mol-ecule. The sulfonate group is disordered over two positions with occupancy factors of 0.655 (5) and 0.345 (5). The hexa-aqua-nickel(II) cation inter-acts through hydrogen bonding with eight QOH mol-ecules and two water mol-ecules. The six-membered rings of quinoline show π-π stacking [centroid-to-centroid distances of 3.679 (2) Å and 3.714 (2) Å].
authors.affiliation: Chemistry Department, Hanoi National University of Education, 136 - Xuan Thuy - Cau Giay, Hanoi, Vietnam.
authors.forename: Hai
authors.initials: H
authors.lastname: Le Thi Hong
authors.affiliation: Chemistry Department, Hanoi National University of Education, 136 - Xuan Thuy - Cau Giay, Hanoi, Vietnam.
authors.forename: Vinh
authors.initials: V
authors.lastname: Nguyen Thi Ngoc
authors.affiliation: Chemistry Department, Hanoi National University of Education, 136 - Xuan Thuy - Cau Giay, Hanoi, Vietnam.
authors.forename: Da
authors.initials: D
authors.lastname: Tran Thi
authors.affiliation: Chemistry Department, Hanoi National University of Education, 136 - Xuan Thuy - Cau Giay, Hanoi, Vietnam.
authors.forename: Ngan
authors.initials: N
authors.lastname: Nguyen Bich
authors.affiliation: Chemistry Department, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven (Heverlee), Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Van Meervelt
keywords: crystal structure; hydrogen bonding; quinoline; zwitterion; π–π stacking