Related Experiment Video
Updated: Jan 2, 2026

Author Spotlight: Accelerating Discovery in Microporous Material Chemistry
Published on: October 6, 2023
Two-dimensional layered lanthanide diphosphonates: synthesis, structures and sensing properties toward Fe3+ and
Xiaomin Hou1, Chong-Chong Yan, Xiuling Xu
1Shandong Province Key Laboratory of Applied Mycology, College of Life Science, Qingdao Agricultural University, Changcheng Road 700, Chengyang District, Qingdao 266109, China.
Abstract:
A series of lanthanide diphosphonates, namely Ln(HL)(H2O)2 (Ln = Nd 1, Eu 2, Tb 3 and Er 4), have been synthesized from a semirigid diphosphonate ligand, (5-methyl-1,3-phenylene)bis(methylene)bisphosphonic acid (H4L). These lanthanide diphosphonates have been systematically characterized by using powder and single-crystal X-ray diffraction, elemental analysis, TGA, IR, UV-vis absorption and luminescence techniques. The single-crystal XRD measurements revealed that these compounds all have two-dimensional layered crystal structures. Among these four compounds, 1, 2 and 4 are isostructural and crystallize in the P21/c space group, whereas compound 3 crystallizes in the P21 space group. These compounds display the characteristic emissions of the respective lanthanide ions. The sensing properties of compound 3 were investigated which revealed that it could be used as a luminescent probe for Fe3+ and Cr2O72- with good selectivity and sensitivity.
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...
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,...
Valence Bond Theory
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...
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
Metallic Solids
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....

