Showing papers by "Enrique J. Baran published in 1986"
TL;DR: In this article, a low-temperature form of InVO4, belonging to the α-MnMoO4 structural type, was characterized using X-ray powder diagrams.
26 citations
19 citations
TL;DR: In this paper, the infrared and Raman spectra of Fe 2 P 2 O 7 have been recorded and discussed, and the results point to a bent bridge conformation and to a centrosymmetric space group.
16 citations
TL;DR: In this paper, X-ray powder data for mixed phosphate/vanadate fluoroapatites of the type M 1o(P0 4 )6 _J(V 0 4 )AF2 (with M = Ca, Sr, Ba and x = 1-3) have been obtained from X-Ray powder data and the only structural effect observed is a continuous increase of unit cell dimensions with increased vanadate incorporation.
Abstract: Crystallographic data for mixed phosphate/vanadate fluoroapatites of the type M 1o(P0 4 )6 _J(V 0 4 )AF2 (with M = Ca, Sr, Ba and x = 1—3) have been obtained from X-ray powder data. The only structural effect observed is a continuous increase of unit cell dimensions with increased vanadate incorporation. The IR and Raman spectra show that the V 0 4 3 incorporation has a negligible effect on the strength of the P —O bonds, although a small bond weakening for both tetrahedral oxoanions is observed as the unit cell volume increases. The results are compar able to those reported earlier for similar mixed hydroxyapatites and suggest that the fluoroapatite lattice can be considered as a good “m odel” for the vertebrate hard tissues.
8 citations
TL;DR: In this paper, the thermal degradation of K 2 HPCr 2 O 10, Na 3 PCr 3 O 13 · 3H 2 O, K 3 P 2 Cr 4 O 19 has been investigated by TG and DTA methods.
4 citations
TL;DR: In this article, the infrared and Raman spectra of CaFeSn(PO 4 ) 3 have been recorded and discussed with the aid of a site-symmetry analysis, which allows a deeper insight into the structural and electronic properties of this type of solids.
4 citations
TL;DR: In this article, a vibrational assignment for the internal vibrations of simple polyoxoanions of the PCrnO3-3n+4 type has been proposed, which is essentially built from a central PO4-tetrahedron which share a different number of corners with CrO4 -tetrashedra.
Abstract: The infrared and Raman spectra of polycrystalline samples of K2HPCr2O10, Na3PCr3O13.3H20, K3PCr4O16 and (NH4)3PCr4O16 were recorded and discussed. A general vibrational assignment for the internal vibrations of these species is proposed. The structural characteristics of an interesting series of simple polyoxoanions of the PCrnO3- 3n+4 type have been determined recently1–7. These species are essentially built from a central PO4 -tetrahedron which share a different number of corners with CrO4 -tetrahedra. As part of our present studies on different physico-chemical properties of polyoxoanions, we have investigated the vibrational spectra of crystalline species containing the following anions: HPCr2O2- 10, PCr3O3- 13 and PCr4O3- 16. As the three species have some common structural features, their vibrational spectra can be analyzed and compared in terms of these common building elements, i. e., terminal CrO3 and PO groups and POCr bridges. The interatomic distances in the above mentioned units are ...
3 citations
TL;DR: In this article, the thermal behavior of isomorphous compounds (NH4)3Ga(C2O4) 3·3H2O and (NH 4)3Al(C 2O4 )3·3HO2O were investigated.
Abstract: The IR and Raman spectra and the thermal behaviour of the isomorphous compounds (NH4)3Ga(C2O4)3·3H2O and (NH4)3Al(C2O4)3·3H2O were investigated. Detailed stoichiometries, sustained by TG, DTA and IR spectroscopic analyses, were found in both cases. Different results, associated with the different polarizing powers of the metal cations, were obtained. The first evidence was found of the formation of basic gallium carbonates.
1 citations
TL;DR: Mean amplitudes of vibration for SeOX2 (X=F, Cl, Br), SeOClF and SeOBrCl have been calculated from known spectroscopic data in a wide temperature range as mentioned in this paper.
Abstract: Mean amplitudes of vibration for SeOX2 (X=F, Cl, Br), SeOClF and SeOBrCl have been calculated from known spectroscopic data in a wide temperature range. The results are briefly discussed and some comparisons with related species are made.
1 citations
Journal Article•
1 citations
TL;DR: A detailed factor-group analysis of the internal vibrations of the SO 2-4 ions present in a polycrystalline K 2 In(OH)(SO 4 ) 2 sample, confirms the non-cestrosymmetric space group Cc postulated for this hydroxosulfate as discussed by the authors.