title: Crystal structure of ammonium/potassium trans-bis-(N-methyl-iminodi-acetato-κ(3) O,N,O')chromate(III) from synchrotron data.
abstract: The structure of the title compound, [(NH4)0.8K0.2][Cr(C5H7NO4)2] (C5H7NO4 is methyl-iminodi-acetate; mida), has been determined from synchrotron data. The Cr(III) atom is located on a centre of symmetry and is coordinated by two N atoms and four O atoms of two facially arranged tridentate mida ligands, displaying a slightly distorted octa-hedral coordination environment. The Cr-N and mean Cr-O bond lengths are 2.0792 (14) and 1.958 (14) Å, respectively. The cation site is located on a twofold rotation axis and shows occupational disorder, being occupied by ammonium and potassium cations in a 0.8:0.2 ratio. In the crystal, inter-molecular hydrogen bonds involving the N-H groups of the ammonium cation as donor and the two non-coordinating O atoms of the carboxyl-ate group as acceptor groups consolidate the three-dimensional packing.
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea.
authors.forename: Dohyun
authors.initials: D
authors.lastname: Moon
authors.affiliation: Department of Chemistry, Andong National University, Andong 36729, Republic of Korea.
authors.forename: Jong-Ha
authors.initials: JH
authors.lastname: Choi
keywords: ammonium/potassium salt; bis­(methyl­iminodi­acetato)­chromate(III) ion; crystal structure; hydrogen bonding; mida; synchrotron radiation; trans-facial configuration