Synthesis and characterization of nano-chambersite

Chambersite (Mn₃B₇O₁₃Cl) is both a rare inorganic macromolecular manganese chloroborate and a rare mineral. The chambersite deposit was firstly discovered in Jixian, Tianjin, China, which is the only mineable chambersite deposit in the world. Due to its unique multi-element composition and structure type, it has great application potential as a light-emitting material in biological anti-virus, anti-tumor, and anti-microbial applications, as well as a nuclear-protection and LED applications. However, as yet there are few reports on the material science of chambersite. Rare-earth and transition-group ion-activated borate are important constituent systems in luminescent materials. In this paper, nano-chambersite and rare-earth-element Eu³⁺-doped nano-chambersite were successfully synthesized by Sol-Gel method. The crystal structure of the nano-chambersite was characterized by X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The performance comparison between natural chambersite and synthetic chambersite was provided to provide a basis for the rational development and utilization of chambersite. The results show that the artificially synthesized chambersite has a spherical shape with a particle size of less than 50 nm, and has the same phase structure as natural chambersite. It belongs to the orthorhombic system and has a structure similar to that of spinel. The inter planar spacing of (010) is 0.8565 nm. Under 490 nm excitation light, the natural chambersite, artificially synthesized chambersite, and rare-earth-element Eu³⁺-doped chambersite crystal all showed a Mn²⁺ emitting center. The Mn²⁺ that filled the center of the tetrahedral lattice site of the crystal exhibited a green emission, whereas the Mn²⁺ that filled the center of the octahedral lattice site of the crystal exhibited a red emission. The artificially synthesized chambersite showed a unique red shift of the emission spectrum with increases in the emitting-light wavelength. This unique phenomenon is beneficial to the conversion of cold and warm luminescence. Eu³⁺ doping in the artificially synthesized chamversite further increased the intensity of the luminescence.