Infrared Studies of Water in Crystalline Hydrates: K2CuCl4•2H2O

1974 ◽  
Vol 52 (7) ◽  
pp. 1029-1041 ◽  
Author(s):  
Gwen H. Thomas ◽  
Michael Falk ◽  
Osvald Knop
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Distinct Type ◽  
Vibrational Coupling ◽  
Infrared Studies ◽  
Crystalline Hydrates

Infrared spectra of polycrystalline K2CuCl4•2H2O at different degrees of deuteration were recorded, between 4000 and 300 cm−1, at temperatures from −160 to 90 °C. The spectra confirm the existence of only one crystallographically distinct type of water molecule in the structure, on sites of symmetry C2r. Vibrational coupling of the bending fundamentals of the water molecule has been analyzed in detail. It is shown that the existence and magnitude of such coupling may be used to predict, from the spectrum of a hydrate, the manner in which a water molecule participates in the crystal structure. The structure and the vibrational spectra of K2CuCl4•2H2O are compared with those of the closely related CuCl2•2H2O.

Infrared Studies of Water in Crystalline Hydrates: Sodium Nitroprusside Dihydrate, Na2[Fe(CN)5NO]•2H2O

1971 ◽  
Vol 49 (9) ◽  
pp. 1413-1424 ◽  
Author(s):  
Michaela Holzbecher ◽  
Osvald Knop ◽  
Michael Falk
Keyword(s):  
Water Molecule ◽  
Sodium Nitroprusside ◽  
Infrared Spectra ◽  
Structure Determination ◽  
The Other ◽  
Water Molecules ◽  
Infrared Studies ◽  
Increasing Temperature ◽  
Crystalline Hydrates ◽  
The Ideal

Infrared spectra of polycrystalline Na2[Fe(CN)5NO] 2H2O at different degrees of deuteration were studied as a function of temperature. The single peaks observed for the bending fundamentals of isotopically dilute H2O and D2O show that all the water molecules are equivalent, as required by Manoharan and Hamilton's structure determination; the doublets observed for the three fundamentals of isotopically dilute HDO show that the water molecules are asymmetric. Doublet separation decreases gradually with increasing temperature, indicating decreasing asymmetry. The water molecule appears to orient itself so as to maximize the strength of one [Formula: see text] bond, while the other OH group interacts only very weakly with another CN group. The hitherto unknown extent to which the nitroprusside ion deviates from the ideal C4v symmetry has been estimated from the 13C14N stretching spectrum. The 15N16O and 14N18O stretching spectrum was used to confirm that only one type of NO group is present in the crystal, and hence that all nitroprusside ions are equivalent.

Infrared Studies of Water in Crystalline Hydrates: K2FeCl5·H2O (Erythrosiderite) and Related Aquopentachloroferrates(III)

1975 ◽  
Vol 53 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Michael Falk ◽  
Chung-Hsi Huang ◽  
Osvald Knop
Keyword(s):  
Water Molecule ◽  
Infrared Spectra ◽  
Water Molecules ◽  
High Charge ◽  
Infrared Studies ◽  
Approximate Location ◽  
Crystalline Hydrates

Infrared spectra of M2[FeCl5(H2O)] (M = K, Rb, NH4) at different degrees of deuteration were recorded, between 4000 and 300 cm−1, at 30 and −160 °C. The spectra of the three compounds were closely similar, as was that of natural K2[FeCl5(H2O)] (erythrosiderite). They indicate the existence of only one type of water molecule in the structure. The water molecules are symmetric, well separated from one another, and engage in O—H … Cl bonds with O … Cl distances of about 3.22 Å, as estimated from the OH and OD stretching frequencies. These conclusions support the structure proposed for K2[FeCl5(H2O)] by Bellanca and lead to approximate location of the H atoms. The observed mixing of the librational and translational modes, which occurs when the frequencies of translational modes are high, may be characteristic of H2O molecules coordinated to cations of high charge.

New Alkali Metal and Tetramethylammonium Tetrafluoroarsenates(III), Their Vibrational Spectra and Crystal Structure of Cesium Tetrafluoroarsenate(III)

2004 ◽  
Vol 69 (2) ◽  
pp. 339-350 ◽  
Author(s):  
Peter Klampfer ◽  
Primož Benkič ◽  
Antonija Lesar ◽  
Bogdan Volavšek ◽  
Maja Ponikvar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Alkali Metal ◽  
Infrared Spectra ◽  
Vibrational Spectra

The title compounds were synthesised by the reaction of alkali metal and tetramethylammonium fluorides with liquid AsF3. Crystal structure of CsAsF4 was determined. Raman and infrared spectra of the title compounds were analysed.

The Vibrational Spectra and Structure of Crystalline Oxanilide

1979 ◽  
Vol 33 (1) ◽  
pp. 32-36 ◽  
Author(s):  
G. N. R. Tripathi ◽  
J. E. Katon
Keyword(s):  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Trans Configuration ◽  
Spectral Features ◽  
Vibrational Coupling ◽  
Laser Raman ◽  
Fundamental Frequencies

Laser Raman and infrared spectra of crystalline oxanilide have been investigated in the region 4000 to 40 cm−1. Spectral features support a trans configuration for the molecule. Vibrational coupling between the two phenyl groups is observed to be negligible. The fundamental frequencies identified in the spectra are tentatively assigned to approximate amide and phenyl modes.

Infrared studies of water in crystalline hydrates: gypsum, CaSO4•2H2O

1969 ◽  
Vol 47 (8) ◽  
pp. 1361-1368 ◽  
Author(s):  
V. Seidl ◽  
Osvald Knop ◽  
Michael Falk
Keyword(s):  
Hydrogen Bonds ◽  
Isotopic Dilution ◽  
Water Molecules ◽  
Spectral Features ◽  
Vibrational Coupling ◽  
Fundamental Frequencies ◽  
Infrared Studies ◽  
The Difference ◽  
Crystalline Hydrates

Infrared spectra of partially deuterated hydrates yield the fundamental frequencies of isotopically dilute H2O, D2O, and HDO molecules. Isotopic dilution eliminates vibrational coupling and allows the determination of the total number of crystallographically distinct water molecules in the crystal. It also yields the number of distinct symmetric (C2v) and asymmetric (Cs) water molecules. The results for gypsum show that all the water molecules are equivalent and that they are asymmetric, in agreement with crystallographic results. The extent of asymmetry is measured by the difference between the two OH stretching frequencies of HDO molecules, which is 90 cm−1. This corresponds to an estimated difference of 0.02 Å in the [Formula: see text] distances of the two hydrogen bonds. The spectra of partially deuterated gypsum show clearly that spectral features previously explained by the presence of two sets of distinct water molecules or by proton tunnelling, are in fact due to vibrational coupling.

Infrared Spectra of the Ammonium Ion in Crystals. I. Ammonium Hexachloroplatinate(IV) and Hexachlorotellurate(IV)

1975 ◽  
Vol 53 (18) ◽  
pp. 2675-2682 ◽  
Author(s):  
Ian A. Oxton ◽  
Osvald Knop ◽  
Michael Falk
Keyword(s):  
Infrared Spectra ◽  
Distinct Type ◽  
Ammonium Ion ◽  
Ammonium Ions ◽  
Bending Vibrations ◽  
Vibrational Coupling

Infrared spectra of polycrystalline (NH4)2PtCl6 and (NH4)2TeCl6 at various degrees of deuteration were recorded between 4000 and 1000 cm−1 at 30 and −165 °C. The stretching and bending vibrations of NH4+, NH3D+, NH2D2+, NHD3+, and ND4+ ions in these two compounds were systematically examined. The observed fundamentals were unambiguously assigned by analogy with the vibrations of the partially deuterated methanes. The spectrum of isotopically dilute NH3D+ confirms the existence of only one crystallographically distinct type of ammonium ion in the structure, on sites of Td symmetry. Vibrational coupling of neighboring ammonium ions was not detected.

Infrared Studies of Water in Crystalline Hydrates: LiI.3H2O

1971 ◽  
Vol 49 (3) ◽  
pp. 347-351 ◽  
Author(s):  
George Brink ◽  
Michael Falk
Keyword(s):  
Hydrogen Bond ◽  
Water Molecule ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Infrared Studies ◽  
Librational Motion ◽  
Increasing Temperature ◽  
Crystalline Hydrates

The infrared spectra of undeuterated and partially deuterated LiI.3H2O were recorded between 4000 and 1000 cm−1. The splitting of the fundamentals of isotopically dilute HDO indicates that the water molecules are distorted and form one strong, linear OH … I− hydrogen bond and one weak, non-linear hydrogen bond. The non-equivalence of the two hydrogens of the water molecule disagrees with the space group P63mc − C6υ4 for this hydrate, proposed on the basis of X-ray diffraction studies. It is concluded that the space group, including hydrogens, is one of lower symmetry, P63 − C66. The gradual broadening and convergence of the HDO fundamentals at increasing temperature is explained by increasing librational motion of the water molecules.

ChemInform Abstract: BaN3Cl: Synthesis, Crystal Structure, Vibrational Spectra and Thermal Decomposition of Barium Azide Chloride.

ChemInform ◽  
2009 ◽  
Vol 40 (2) ◽  
Author(s):  
Bjoern Blaschkowski ◽  
Harald Balzer ◽  
Hans-Lothar Keller ◽  
Thomas Schleid
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Vibrational Spectra

Calcium Carbodiimide Compounds Revisited – Syntheses, Single Crystal Structure Determination and Vibrational Spectra of Ca11N6[CN2]2, Ca4N2[CN2] and Ca[CN2]

2008 ◽  
Vol 63 (5) ◽  
pp. 530-536 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Raman Spectrum ◽  
Single Crystal ◽  
Single Crystals ◽  
Vibrational Spectra ◽  
Structure Determination ◽  
X Ray ◽  
Characteristic Features ◽  
Reported Data ◽  
Correct Data

Single crystals of Ca11N6[CN2]2 (dark red needles, tetragonal, P42/mnm (no. 136), a = 1456.22(5), and c = 361.86(2) pm, Z = 2), Ca4N2[CN2] (transparent yellow needles, orthorhombic, Pnma (no. 62), a = 1146.51(11), b = 358.33(4), and c = 1385.77(13) pm, Z = 4) and Ca[CN2] (transparent, colorless, triangular plates, rhombohedral, R3̅m (no. 166), a = 369.00(3), and c = 1477.5(3) pm, Z = 3) were obtained by the reaction of Na2[CN2], CaCl2 and Ca3N2 (if demanded by stoichiometry) in arc-welded Ta ampoules at temperatures between 1200 - 1400 K. Their crystal structures were re-determined by means of single crystal X-ray structure analyses. Additionally, the Raman spectra were recorded on these same single crystals, whereas the IR spectra were obtained with the KBr pellet technique. The title compounds exhibit characteristic features for carbodiimide units with D∞h symmetry (d(C-N) = 121.7 - 123.8 pm and ∡ (N-C-N) = 180°). The vibrational frequencies of these units are in the expected range (Ca11N6[CN2]2: νs = 1230, νs = 2008; δ = 673/645/624 cm−1; Ca4N2[CN2]: νs = 1230, νs = 1986; δ = 672/647 cm−1; Ca[CN2]: νs = 1274, νs = 2031, δ = 668 cm−1). The structural results are more precise than the previously reported data, and with the newly attained Raman spectrum of Ca11N6[CN2]2 we correct data reported earlier.

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