Dilead(II) hydrogen­phosphite dinitrate

In the title compound, Pb2(HPO3)(NO3)2, the two distinct Pb2+ ions (both with site symmetry m) adopt irregular PbO10 coordination polyhedra. The structure is completed by two distinct nitrate groups (in which one O atom and the N atom have m site symmetry for both ions) and an HPO3 2− anion (in which one O atom and the P and H atoms have m site symmetry). The connectivity of the PbO10, NO3 and HPO3 units in the crystal structure results in a three-dimensional network

Crystal structure of NaCd(H2PO3)3·H2O and spectroscopic study of NaM(H2PO3)3·H2O, M= Mn, Co, Ni, Zn, Mg and Cd

NaCd(H2PO3)3·H2O was synthesized in solution and its structure was studied by single-crystal X-ray diffraction. It crystallizes in the orthorhombic system (Pbca, Z = 8) with the cell parameters: a = 9.2895(14) Å, b = 15.124(2) Å, c = 15.0592(12) Å. Final residual factors R/Rw are 0.0297/0.0790. Both Na+ and Cd2+ are octahedrally coordinated, [NaO6] and [CdO6] share edges to form zigzag chains along [1 0 0]. The 3D framework is build upon these chains which are interconnected by H2PO3 pseudo-pyramids and an intricate network of weak hydrogen bonds. NaCd(H2PO3)3·H2O belongs the series of isostructural phosphites NaM(H2PO3)3·H2O (M = Mn, Co, Ni, Zn and Mg). IR spectroscopic studies show the bands confirming the presence of the phosphite H2PO32− anion in the whole series NaM(H2PO3)3·H2O, M = Mn, Co, Ni, Zn, Mg and Cd. The UV–Vis spectroscopy was used for characterizing the d–d transitions in the Mn, Co and Ni phosphites.The financial support from Centre National de Recherche Scientifique et Technique (CNRST) (Morocco) (URAC 19). The institutional research plan No. AVOZ10100521 of the Institute of Physics and the grant “Praemium Academiae” of the Academy of Sciences of the Czech Republic

Removal of methylene blue with a highly effective hydroxyapatite-silica nanocomposite

Two Hydroxyapatite-silica nanocomposite adsorbent (HApS220 and HApS230) were successfully synthesized using sol-gel technique. The samples were characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), which confirmed the formation of a Hydroxyapatite-silica nanocomposite. The synthesized powders were then used for adsorption of methylene blue (MB). Both compounds possessed high absorption capacities, the adsorption equilibrium time is around 10 min. HApS230 sample shows higher adsorption capacity compared to HApS220. Furthermore, isotherm studies show that the adsorption used is an ion exchange process and that Temkin isotherm describes the adsorption better compared to the Langmuir and Freundlich and Dubinin-Radushkevich isotherms. Kinetics studies confirm that the adsorption follow the pseudo-second order model and chemisorption mechanism. Thermodynamics’ studies confirm that the adsorption of MB on HApS samples is a spontaneous endothermic process. The average removal effectiveness of MB reached about 89.02% (6.389 mg/g adsorption capacity) and 91.36% (6.55 mg/g adsorption capacity) for HApS220 and HApS230 respectivel

Ba(H2PO3)2.0.5H2O: Synthesis, crystal structure optimization, vibrational study, DFT computation and application as a corrosion inhibitor

This investigation involved the synthesis of barium phosphite Ba(H2PO3)2.0.5H2O by reacting barium chloride with phosphorous acid. The physical characteristics, FT-IR spectra, and X-ray diffraction were employed to validate the composition of the synthesized substance, and powder X-ray diffraction (PXRD) was used to determine the phase purity. The optimal molecular geometry, infrared intensities were calculated using density functional theory (DFT/B3LYP) methods with the LanL2DZ basis set. The HOMO-LUMO properties and geometries of this compound have been determined and discussed. The computational structural parameters are generally in agreement with the experimental investigations. The theoretical infrared for the title compound has been constructed. Additionally, the anti-corrosion properties of this compound were investigated in an acidic solution using weight loss and electrochemical techniques. The results showed good effectiveness, indicating the formation of a protective film on the C38 surface

Physicochemical study of magnesium zinc codoped-hydroxyapatite

Mg-Zn-doped hydroxyapatites in the system Ca9.4-xMg0.6Znx(PO4)6(OH)2 (x= 0, 0.1, 0.2, 0.4 and 0.6) were synthesized via sol-gel method. The obtained powder was calcined at 600°C and 700°C. X-ray diffraction (XRD) patterns and Infra-Red (IR) spectra confirmed the formation of pure hydroxyapatite up to 2% Zn content (a trace of β-pyrophosphate is detected for x=0), while a mixture of hydroxyapatite and β-TCP was formed for 4 mol%. With 6 mol%, only β-TCP formed. Moreover, at 700°C, all powders turned to be composed of solely β-TCP. The unit cell constants have also been calculated and match well with hexagonal (P63/m) hydroxyapatite