Related Experiment Video
Updated: Jun 23, 2026

Synthesizing Sodium Tungstate and Sodium Molybdate Microcapsules via Bacterial Mineral Excretion
Published on: January 30, 2018
Cu2O hollow spheres: synthesis, characterization and magnetic property
Hua Zhang1, Zhou Di, Lina Zhang
1School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China.
Abstract:
Cu2O hollow spheres with thin shells were synthesized using poly(vinylpyrrolidone) (PVP) as the template in deionized water. In this process, CuAc2.H2O was reduced by acerbic acid in the presence of PVP and sodium hydroxide. Techniques, including XRD, XPS, TEM and HRTEM were used to characterize the morphology, structure and composition of the as-prepared nanomaterials. The results revealed that the average diameter of polycrystalline Cu2O hollow spheres is about 200 nm, with the shells as thin as approximately 10 nm. The formation mechanism, of these hollow spheres was studied. Magnetic property of the sample demonstrates a paramagnetic behavior at 15 K, and it might be attributed to the hollow-sphere structure of the diamagnetic Cu2O.
Related Concept Videos
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 eye.
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...
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...
