The cadmium-rich RERh ₂ Cd ₂₀ phases form with the whole series of rare earth elements. EuRh ₂ Cd ₂₀ and YbRh ₂ Cd ₂₀ exhibit stable divalent ground states.

Lanthanides have seen rapid growth in the pharmaceutical and biomedical field, thus necessitating the development of hybrid metal–organic materials capable of exerting defined biological activities. Ternary hybrid lanthanide compounds were synthesized through reaction systems of Ln(III) (Ln = La, Nd, Eu) involving the antioxidant flavonoid chrysin (Chr) and 1,10-phenanhtroline (phen) under solvothermal conditions, thus leading to pure crystalline materials. The so-derived compounds were characterized physicochemically in the solid state through analytical (elemental analysis), spectroscopic (FT-IR, UV-visible, luminescence, ESI-MS, circular dichroism, ¹⁵¹Eu Mössbauer), magnetic susceptibility, and X-ray crystallographic techniques. The analytical and spectroscopic data corroborate the 3D structure of the mononuclear complex assemblies and are in line with theoretical calculations (Bond Valence Sum and Hirshfeld analysis), with their luminescence suggesting quenching on the flavonoid-phen electronic signature. Magnetic susceptibility data suggest potential correlations, which could be envisioned, supporting future functional sensors. At the biological level, the title compounds were investigated for their (a) ability to interact with bovine serum albumin and (b) antibacterial efficacy against Gram(−) (E. coli) and Gram(+) (S. aureus) bacteria, collectively revealing distinctly configured biological profiles and suggesting analogous applications in cellular (patho)physiologies.

Metal tin‐(II)‐borates are rarely studied mainly due to the susceptibility of either oxidation into tin(IV) or disproportionation into elemental tin(0) and tin(IV). We report mullite‐type SnAlBO ₄ and SnGaBO ₄ ceramics produced by conventional solid‐state synthesis in sealed quartz tubes at low pressure of 10 ^–7 MPa. Both compounds are isostructural to PbAlBO ₄ as confirmed by Rietveld refinements of powder X‐ray data. The crystal structures are highly influenced by the stereochemical activity of the 5s ² lone electron pair of the Sn ²⁺ cation measured by the Wang–Liebau eccentricity parameter. To further consolidate the structural features ¹¹⁹ Sn Mössbauer, solid state NMR, Raman, IR and UV/vis spectroscopic measurements are performed. The ¹¹⁹ Sn Mössbauer isomer shifts and the quadrupole splitting values confirm the SnO ₄ coordination and Sn(II) valence states. Solid state ¹¹ B, ²⁷ Al and ¹¹⁹ Sn NMR spectra provided insights into the local crystal‐chemical environment. The vibrational properties are discussed from group theoretical analysis to mode assignments. SnAlBO ₄ and SnGaBO ₄ , respectively, possess an electronic band gap of 3.73(9) and 3.21(4) eV calculated from the diffuse reflectance UV/Vis spectra.

With M ^III M ^I [B(SO ₄ ) ₂ ] ₄ (M ^III = Bi ³⁺ , Sb ³⁺ , Lu ³⁺ ; M ^I = H ₃ O ⁺ , NO ₂ ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ ), we recently described the first modular system within borosulfate chemistry comprising a three‐dimensional anion. Herein, we shed light on the respective series of antimony compounds SbX[B(SO ₄ ) ₂ ] ₄ (X = Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Ag ⁺ , Tl ⁺ , NO ⁺ , NH ₄ ⁺ ). While maintaining the same anionic topology, the compounds crystallize in the space groups I (no. 82), P (no. 81), and C 2 (no. 5) and are strongly influenced by the lone pair of antimony as well as the size of the monovalent cations. In the course of this investigation SbX[B ₄ O ₂ (SO ₄ ) ₆ ] (X = Li ⁺ , Na ⁺ ) were discovered. This borosulfate with a one‐dimensional anion comprising B─O─B bridges crystallizes in the space group Pnma (no. 62) and features a new structure type. ¹²¹ Sb Mössbauer spectra revealed negative isomer shifts of almost −22 mm·s ⁻¹ not observed before and hinting towards a very weak coordination behavior of the borosulfate anion. The spectra are confirmed by DFT calculations. Furthermore, single crystal X‐ray diffraction, infrared spectroscopy, thermal analysis, and temperature programmed X‐ray diffraction experiments were carried out.

We report on temperature‐dependent structural and spectroscopic properties of two new members of the mullite‐type ceramics SnAlBO ₄ and SnGaBO ₄ . In‐situ X‐ray powder diffraction (XRPD) demonstrates positive thermal expansion behavior for all orthorhombic lattice parameters between 13 and 840 K. The lattice thermal expansion is modeled by Grüneisen first‐order approximation, where the vibrational energy is calculated by the Debye–Einstein–anharmonicity (DEA) approach. Although the thermal changes of the metric parameters do not show any discontinuity, the double‐Debye model and low‐temperature thermal analysis leave hints for subtle displacive changes. Splitting of the tin‐doublets of the ¹¹⁹ Sn Mössbauer spectra at low temperature is assumed to be associated with structural modulation although the temperature‐dependent Raman spectra could not support these findings. The modulation could either be dynamic which requires much longer thermal equilibration than the speed of the data collection for XRPD and Raman spectroscopy. Selective Raman mode frequencies are analyzed using a modified Klemens model, which helps to understand the thermal anharmonic behaviors of the SnO ₄ , MO ₆ , and BO ₃ polyhedra as a function of temperature.

The susceptibility of either oxidation into Sn(IV) or disproportionation into Sn(IV) and Sn(0) limits the study of metal tin‐(II)‐borate ceramics. We report mullite‐type SnCrBO ₄ and SnVBO ₄ synthesized in sealed quartz tubes by conventional solid‐state method. X‐ray powder diffraction data Rietveld refinements confirm that both compounds are isostructural to Pb M BO ₄ phases for M = Al, Ga, Cr, Mn, and Fe. The end‐members show a complete miscibility within the Sn(Cr _{1− x} V _x )BO ₄ solid solution. Both the microstructural (average crystallite size, microstrain, and degree of crystallinity) and crystal structural (metric parameters, bond lengths, polyhedral volume, and polyhedral distortion) parameters are observed with respect to the compositional x ‐value. The stereochemical activity of the 5 s ² lone electron pairs of Sn ²⁺ cations has been measured by using the Wang–Liebau eccentricity parameter. The structural features are complemented by ¹¹⁹ Sn Mössbauer, Raman, and Fourier‐transformed infrared spectroscopy. The ¹¹⁹ Sn Mössbauer isomer shifts and the quadrupole splitting values confirm the SnO ₄ coordination and an Sn(II) valence state. The electronic band gap has been calculated from the UV/Vis diffuse reflectance spectra, which slightly increases with successive decrease of the cationic radius from V to Cr. Temperature‐dependent inverse DC magnetic susceptibility suggests that SnCrBO ₄ and SnVBO ₄ are antiferromagnetic and ferromagnetic (FM) with a Néel temperature of 17.2(1) K and a Curie temperature of 29.8(1) K, respectively. Alike the end‐member SnVBO ₄ , Sn(Cr _0.5 V _0.5 )BO ₄ is also found to be a rare FM insulator. The thermal stability decreases with increasing vanadium content in the solid solution.