Infrared absorption spectra of Ag3[PO4, VO4] mixed crystals

1979 ◽  
Vol 44 (3) ◽  
pp. 823-828 ◽  
Author(s):  
Bohumil Hájek ◽  
Alexander Muck ◽  
Olga Smrčková
Keyword(s):  
Mixed Crystal ◽  
Group Analysis ◽  
Factor Group ◽  
Mixed Crystals ◽  
Site Symmetry ◽  
Lattice Vibrations ◽  
Concentration Region ◽  
Site Group ◽  
Infrared Absorption Spectra ◽  
Effective Site

Ag3[PO4, VO4] mixed crystals were prepared in the whole concentration region. For 0-40 mol % vanadate, the mixed crystals are isostructural with the low-temperature modification of Ag3PO4 (Td4, Z = 2); the site group and factor group analysis was performed for this space group. Mixed crystals containing 60% vanadate and more are tetragonal with the structure of Ag3VO4. From the analysis of the infrared spectra it follows that in the cubic mixed crystal with 40 mol % Ag3VO4, the site symmetry T is additionally lowered to the effective site symmetry C3 due to the effect of the lattice vibrations of the types T(F) and R(F).

The infrared absorption spectra of mixed Ag3[AsO4, VO4] crystals

1979 ◽  
Vol 44 (11) ◽  
pp. 3346-3349 ◽  
Author(s):  
Bohumil Hájek ◽  
Alexander Muck ◽  
Olga Smrčková
Keyword(s):  
Absorption Spectra ◽  
Infrared Absorption ◽  
Factor Group ◽  
Mixed Crystals ◽  
Site Symmetry ◽  
Lattice Vibrations ◽  
Space Group ◽  
Infrared Absorption Spectra ◽  
Effective Site

Mixed Ag3[AsO4, VO4] crystals were prepared over the whole concentration range. In the 0-40% mol. Vanadate concentration range the mixed crystals are isostructural with Ag3AsO4 (T4d, Z = 2). Site- and factor group analyses were carried out for this space group and structure. Above 60 mol% vanadate, the mixed crystals are tetragonal with Ag3VO4 structure. It follows from the behaviour of the ν4AsO3-4 vibration that, in cubic mixed crystals with 40 mol% Ag3VO4, the site-symmetry T is reduced to effective site-symmetry C3 by the effect of lattice vibrations of the T(F) and R(F) types.

Study of decreased T site-symmetry in the mixed crystals Ag3(PO4,AsO4)

1980 ◽  
Vol 45 (12) ◽  
pp. 3262-3265 ◽  
Author(s):  
Alexander Muck ◽  
Jindřich Čáp ◽  
Bohumil Hájek
Keyword(s):  
Absorption Spectra ◽  
Infrared Absorption ◽  
Factor Group ◽  
Mixed Crystals ◽  
Site Symmetry ◽  
X Ray ◽  
Powder Samples ◽  
Substitution Type ◽  
Infrared Absorption Spectra ◽  
Effective Site

The system Ag3PO4-Ag3AsO4 has been studied by X-ray analysis of the powder samples and infrared absorption spectra. Formation of cubic mixed crystals of the substitution type has been found within the whole concentration range. For the tetrahedral anions at the site T(2) lowering of the site-symmetry to the effective site-symmetry C3 has been found on the basis of the site-and factor-group analyses of the space group Td4.

Vibration spectra of mixed crystals Sc(PO4, VO4) and Y(PO4, VO4)

1982 ◽  
Vol 47 (4) ◽  
pp. 1176-1183 ◽  
Author(s):  
Alexander Muck ◽  
Olga Smrčková ◽  
Bohumil Hájek
Keyword(s):  
Infrared Spectra ◽  
Group Analysis ◽  
Point Of View ◽  
Mixed Crystals ◽  
Site Symmetry ◽  
Lattice Vibrations ◽  
Vibration Spectra ◽  
Space Group

Infrared spectra of mixed crystals Sc(PO4, VO4) and Y(PO4, VO4) have been studied from the point of view of group analysis. These systems form substitution mixed crystals in tetragonal space group D194h. The anions having proper symmetry Td or D2d in site symmetry D2d exhibit in spectra lowering of the site symmetry to effective C2 as a result of lattice vibrations of the type T(B2).

scholarly journals IR-Spektren kristalliner, wasserfreier Permanganate, Pertechnetate und Perrhenate

1966 ◽  
Vol 21 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Achim Müller ◽  
Bernt Krebs
Keyword(s):  
Ir Spectra ◽  
Crystal Field ◽  
Infrared Absorption ◽  
Group Analysis ◽  
Factor Group ◽  
Site Group ◽  
Absorption Frequencies

The infrared absorption frequencies in the region of the MeO4⊖ fundamental vibrations are reported for several crystalline permanganates, pertechnetates, and perrhenates. On the basis of the IR spectra of the crystals and of additional considerations correct frequencies are assigned to the ν2(E) vibrations of the MeO4⊖ tetrahedra. The influence of the crystal field on the fundamental vibrations of the MnO4⊖, TcO4⊖, and ReO4⊖ ions is discussed, using site group analysis and factor group considerations.

Gitterschwingungsspektren. XIV NiAs-und Fe3Se4 -Struktur / Lattice Vibration Spectra. XIV. NiAs and Fe3Se4 Structure

1975 ◽  
Vol 30 (3) ◽  
pp. 308-311
Author(s):  
H. D. Lutz ◽  
H. Haeuseler ◽  
P. Willich
Keyword(s):  
Defect Structure ◽  
Lattice Vibration ◽  
Group Analysis ◽  
Factor Group ◽  
Vibrational Modes ◽  
Lattice Vibrations ◽  
Normal Coordinate ◽  
Valence Force Field ◽  
Symmetry Coordinates ◽  
Coordinate Treatment

The results of a factor group analysis, the symmetry coordinates and vibrational modes of the lattice vibrations of compounds crystallizing in NiAs structure respectively NiAs defect structure (Fe3Se4 type) are presented. A normal coordinate treatment of the NiAs structure is performed using the GF-matrix-method assuming a valence force field with 3 force constants.

A study of mixed crystals in the InPO4-InVO4 system and their infrared spectra

1985 ◽  
Vol 50 (7) ◽  
pp. 1465-1469 ◽  
Author(s):  
Bohumil Hájek ◽  
Alexander Muck ◽  
Eva Šantavá
Keyword(s):  
Infrared Spectra ◽  
Factor Group ◽  
Mixed Crystals ◽  
Crystal Symmetry ◽  
Group Approach ◽  
Orthorhombic System ◽  
Site Group

The crystal symmetry was studied for mixed crystals in the InPO4-InVO4 orthorhombic system. The infrared spectra were examined using the site group and factor group approach, and the Td → Cs → C2v correlation was found more appropriate than the Td → C2v → D2h correlation.

The electronic spectra of mixed crystals

1963 ◽  
Vol 271 (1345) ◽  
pp. 207-217 ◽  
Keyword(s):  
Intermolecular Interactions ◽  
Electronic Spectra ◽  
Mixed Crystal ◽  
Electronic States ◽  
Dipole Approximation ◽  
Mixed Crystals ◽  
Excited Electronic States ◽  
Guest Molecules ◽  
Rough Approximation ◽  
Crystal Properties

The excited electronic states of dilute mixed crystals are discussed in terms of the theory of intermolecular interactions in dipole-dipole approximation. Resonance interactions of the Davydov type, which are of the first importance in pure crystals, are absent. However, interactions between host and guest molecules are generally of com parable importance to second-order interactions in pure crystals, and lead to similar changes in absolute absorption intensities and polarization ratios. There is a substantial departure from oriented-gas behaviour, which can be regarded as only a rough approximation to mixed crystal properties.

Tuning of the exchange interaction and the Curie temperature by mixed crystal formation of the bridging anionic ligands

2019 ◽  
Vol 55 (18) ◽  
pp. 2652-2655 ◽  
Author(s):  
Tristan Neumann ◽  
Michał Rams ◽  
Zbigniew Tomkowicz ◽  
Inke Jess ◽  
Christian Näther
Keyword(s):  
Critical Temperature ◽  
Curie Temperature ◽  
Exchange Interaction ◽  
Coordination Polymers ◽  
Mixed Crystal ◽  
Mixed Crystals ◽  
Exchange Constant ◽  
Crystal Formation ◽  
Anionic Ligands ◽  
Mixed Crystal Formation

A strategy to continuously tune the exchange constant J and the critical temperature Tc in the 1D coordination polymers [Co(NCS)x(NCSe)2−x(pyridine)2]n is reported. For such mixed crystals, prepared by annealing and from solution, an increase of J and Tc with increasing selenocyanate content is observed.

Raman study of the structural properties of KNO3(II)

1977 ◽  
Vol 55 (7) ◽  
pp. 1242-1250 ◽  
Author(s):  
M. H. Brooker
Keyword(s):  
Single Crystals ◽  
Structural Properties ◽  
Raman Spectra ◽  
Excellent Agreement ◽  
Room Temperature ◽  
Group Analysis ◽  
Factor Group ◽  
Spectral Features ◽  
Space Group ◽  
Raman Study

Raman spectra of oriented single crystals of KNO3(II) have been recorded at 298 and 77 K. At both temperatures the data are in excellent agreement with the factor group analysis based on the generally accepted Pmcn space group. Additional spectral features observed near room temperature suggest the presence of a significant number of disordered nitrate groups on alternate lattice sites, although the majority of nitrate groups occupy the ordered sites. As the temperature is lowered, the disordered groups freeze out until near the temperature of reported electrical anomalies (213 K) only the ordered sites are occupied. Improved resolution has resulted in detection of a number of new spectral features while improved depolarization data have resulted in reassignment of several peaks.

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