Related Experiment Video
Updated: Jun 23, 2026

X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects
Published on: June 8, 2016
Crystal structure of Na2Mg2NiH6 revisited
Maria Orlova1, Jean-Philippe Rapin, Klaus Yvon
1Laboratory of Crystallography, University of Geneva, Quai Ernest-Ansermet 24, 1211 Geneva, Switzerland.
Abstract:
The crystal structure of Na(2)Mg(2)NiH(6) as published by Kadir and Noreus (Inorg. Chem. 2007, 46, 2220-2223) is revised. While the reported space group symmetry and cell parameters are correct, the Mg and hydride positions need to be interchanged. Consequently, the tetrahedral [NiH(4)](4-) complexes are stabilized by both Na(+) and Mg(2+) ions and not by Na(+) ions only, as was stated by the authors. The metal-hydrogen bond distances of the revised structure model differ by up to 0.6 A from those reported and are more in line with those usually observed in these sorts of hydrides. An overview of the known cation configurations around solid-state [NiH(4)](4-) complexes is given.
More Related Videos
Related Concept Videos
Ionic Crystal Structures
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Metallic Solids
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Ionic Bonding and Electron Transfer
Coordination Compounds and Nomenclature
Structures of Solids

