Reverse dichromatism in gem andalusite related to total pleochroism of the Fe2+-Ti4+ IVCT

Synthesis of Controllable Superparamagnetic Nano Fe3O4 Based on Reduction Method for Colloidal Clusters of Magnetically Responsive Photonic Crystals

“…Meanwhile, when sodium hydroxide is added to the system, the broadspectrum absorption peak had a higher absorbance, indicating that sodium hydroxide facilitated the charge transfer between Fe 3+ and Fe 2+ . This broad-spectrum absorption was consistent with the phenomenon produced by mixed valence binuclear complexes [50][51][52], which was the formation of binuclear iron complexes in the system. The specific synthesis mechanism is shown in Figure 6e, where Fe 3+ was eventually converted to FeOOH in an alkaline environment, and if VC was not added to the system at this time, then inevitably FeOOH would be rapidly generated to Fe 2 O 3 impurities mixed in the final product; if VC was added to the system, a binuclear iron complex would be formed, and then FeOOH would be immediately combined with the complex to further generate pure Fe 3 O 4 at high temperature and avoid the generation of Fe 2 O 3 impurities.…”

Magnetic response of photonic crystals based on nucleating agents of binuclear complexes

“…This is in agreement with the phenomenon described in the literature for mixed-valence binuclear complexes. [50][51][52][53][54][55][56][57][58] In such complexes, an inter-valence charge transfer absorption band (IVCT) is formed between metals of different valence states that typically exhibit a broad absorption peak across the entire visible range. The precursors were then further determined by infrared spectroscopy, and the results are shown in Fig.…”