Related Experiment Video
Updated: Dec 29, 2025

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 a new polyoxometalate (POM) compound with a high level of crystallographic disorder
Eliska Skorepova1, Ali Harchani2, Mohamed Mongi Ftini3
1Institute of Physics ASCR, Na Slovance 2, 182 21 Praha 8, Czech Republic.
Abstract:
The crystal structure, Hirshfeld surface analysis and spectroscopic analysis of a new polyoxometalate (POM) compound, namely, nonakis(2-methoxyaniline) bis(diphosphopentamolybdate) trihydrate, (C7H9NO)9[P2Mo5O23]2·3H2O, is reported. The title compound was synthesized using the solution method and was structurally characterized by single-crystal X-ray diffraction, which revealed P-1 symmetry. A study of the intermolecular interactions using Hirshfeld surface analysis confirmed that the hydrogen-bonding interactions play the dominant role in the stability of the crystal structure. The refinement was complicated by extensive disorder affecting 11 of the 16 ions and molecules in the asymmetric unit. IR and UV-Vis spectroscopic techniques were used to identify the vibrational modes and to classify this compound as an insulator.
Related Concept Videos
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
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....
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,...
Polymer Classification: Crystallinity
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Structures of Solids

