A5048616526- Chemical Synthesis and Characterization
- Radioactive element chemistry and processing
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Thermal and Kinetic Analysis
- Inorganic Chemistry and Materials
- Crystal Structures and Properties
- Polyoxometalates: Synthesis and Applications
- Zeolite Catalysis and Synthesis
- Metal-Organic Frameworks: Synthesis and Applications
- MXene and MAX Phase Materials
- Bone Tissue Engineering Materials
- Chemical Thermodynamics and Molecular Structure
- Layered Double Hydroxides Synthesis and Applications
- Crystallography and molecular interactions
- Titanium Alloys Microstructure and Properties
- Iron oxide chemistry and applications
- Plant tissue culture and regeneration
- Energetic Materials and Combustion
- Nuclear materials and radiation effects
- Free Radicals and Antioxidants
- Bioenergy crop production and management
- Proteins in Food Systems
- Advanced oxidation water treatment
- Building materials and conservation
Universidad de Oviedo
2004-2024
University of Aveiro
2006-2008
Instituto Nacional del Carbón
1998
Instituto de Química Física Blas Cabrera
1998
Crystalline α-zirconium phosphate, Zr(HPO4)2·H2O, was obtained by direct precipitation of soluble salts zirconium(IV) with phosphoric acid. The fresh compound transforms, hydrolysis, into amorphous or semicrystalline hydroxophosphates a P/Zr molar ratio less than two. These facts contradict the formation mechanism zirconium phosphates admitted researchers for over more 40 years. materials are characterized chemical, textural, and thermal analysis, powder X-ray diffraction, scanning electron...
The simultaneous intercalation of two or more n-alkylamines into α-titanium phosphate, Ti(HPO4)2·H2O, has been investigated. large n-alkylamine molecules observed to be faster if there is a shorter alkyl chain amine, acting as catalyst, yielding at completion single amine intercalates. New individual phases containing different amines are obtained. In the case vapor mixture several (CnH2n+1NH2, n = 2−8), compound obtained depends on reaction time, providing selectivity. morphology and...
Organically templated titanium phosphate, (C2H5NH3)[Ti(H1.5PO4)(PO4)]2·H2O, has been prepared by hydrothermal synthesis from titanium(IV) chloride, phosphoric acid, and ethylamine. The structure of this material characterized synchrotron X-ray powder diffraction, 1H, 13C, 15N, 31P (including 1H{FS-LG}-1H HOMCOR, 1H{FS-LG}-31P HETCOR, 1H-1H DQ-SQ, 13C{31P} REDOR) MAS NMR, FTIR spectroscopies thermal analyses (TG DSC). Its triclinic was solved in the space group P1 (No. 1) with following final...
The thermal transformations of gamma-titanium phosphate, Ti(PO(4))(H(2)PO(4)) x 2 H(2)O, have been studied by analyses (thermogravimetry (TG) and differential analysis (DTA)) variable-temperature (31)P magic-angle spinning (MAS)/CPMAS 2D (31)P-(31)P spin-exchange NMR. structure this material has refined from synchrotron powder X-ray diffraction data (monoclinic, P2(1), a = 5.1811(2) A, b 6.3479(2) c 23.725(2) beta 102.57(1) degrees). Vyazovkin's model-free kinetic algorithms applied to...
An organically templated titanium phosphate, (C6H13NH3)[Ti(HPO4)(PO4)]·H2O, has been prepared by hydrothermal synthesis from titanium(IV) chloride, phosphoric acid, and n-hexylamine. The structure of this material characterized powder X-ray diffraction (XRD), 1H [including 1H{FS−Lee−Goldburg (LG)}−1H homonuclear correlation (HOMCOR), double quantum (DQ), 1H{FS-LG}−31P cross-polarization (CP) heteronuclear (HETCOR)], 13C, 31P magic-angle spinning (MAS) NMR, Fourier transform infrared (FTIR)...
Iron(III) phosphates have been synthesized directly under mild hydrothermal conditions. The reaction of FeCl3, H3PO4 and (NH2)2CO aqueous solutions at 180 °C leads to the formation four individual compounds: FePO4·2H2O, Fe(NH4)(HPO4)2, Fe2(NH4)(OH)(PO4)2·2H2O Fe(NH3)2PO4. product depends on Fe∶P∶C molar ratio in mixture. effect urea route is discussed.
Using a microcalorimetric technique, we have determined the differential heat of adsorption ethyl- and n-butylamine over α- γ-titanium phosphate phases. The recorded data were compared with those obtained by using N2/77 K adsorption−desorption isotherms, X-ray diffraction peak broadening studies, scanning electron microscopy. At low coverage, measured decreases increasing which means solids superficial heterogeneity. γ-phase external surface is more energetic than α-one. average heats in...
The reaction between natural phlogopite, having the idealized formula KMg3(AlSi3O10)(OH)2, and phenylphosphonic acid under soft conditions (24 h, 80 °C, reflux) originated a new layered material of following composition: [Mg(H2O)2]0.5(AlSi3O6)(O3PC6H5)2·2H2O. mechanism involves rupture trioctahedral layers phlogopite formation basal spacing hydrophobic type that is occupied by groups in pseudomonomolecular arrangement. Simultaneously, mobile K+ ions become partially substituted [Mg(H2O)2]2+...
Fe(NH3)2PO4 is synthesized under mild hydrothermal conditions in the presence of urea. The crystal structure solved for powder X-ray diffraction data. unit cell orthorhombic, a = 10.1058(2) Å, b 6.3676(2) c 7.5714(2) space group Pnma, Z 4. consists three-dimensional network FeO4N2 octahedra and PO4 tetrahedra linked by vertex sharing. Two crystallographically independent ammonia molecules are to iron atom. This compound first solid structurally characterized containing Fe−NH3 bonds.
The open-framework compounds Fe(NH3)2PO4 and Fe(NH4)(HPO4)2 were synthesized by hydrothermal reactions in the H3PO4–(NH2)2CO–FeCl3–H2O system. electron paramagnetic resonance spectra for show an isotropic signal with g = 2, characteristic of high spin Fe(III) ions octahedral environment. Below 22 K compound exhibits a long-range antiferromagnetic ordering which magnetic interactions involve Fe–O–P–O–Fe superexchange pathways. behaviour presence significant ferromagnetic component from 18 to...
n-Alkylamines were intercalated into Ti2O3(H2AsO4)2·2H2O (TiOAs) and Zr2O3(HAsO4)·3H2O (ZrOAs) by exposing the solids to amine vapour. The formulae of intercalation compounds are Ti2O3(H2AsO4)2·1.7CnH2n + 1NH2·2H2O Zr2O3(HAsO4)·0.6CnH2n (n = 3–6), respectively. amines form bimolecular layers in interlayer space polyvalent metal arsenates. changes basal spacing as a function length alkyl chain used for evaluation free area associated with each active centre arsenate layers: 11.8 10.8 Å2...