The effect of pressure on the infrared spectra of the formates of the alkali and alkaline earth metals

1977 ◽  
Vol 30 (5) ◽  
pp. 957 ◽  
Author(s):  
SD Hamann ◽  
E Spinner
Keyword(s):  
Infrared Spectra ◽  
Phase Iii ◽  
Isotopic Dilution ◽  
Temperature Phase ◽  
Effect Of Pressure ◽  
Main Effect ◽  
Crystalline Salt ◽  
Frequency Changes ◽  
Metal Formates ◽  
Sodium And Potassium

The infrared spectra of the solid metal formates HCO2Li, HCO2Li,H2O, HCO2Na, DCO2Na, H13CO2Na, HCO2K, DCO2K, HCO2Rb, DCO2Rb, HCO2Cs, DCO2Cs, (HCO2)2Ca, (HCO2)2Sr, (HCO2)2Ba and (HCO2)2Pb have been measured in the pressure range 0-42 kbar at 25�C. For the sodium salt two new modifications formed at high pressure have been observed, but the potassium, rubidium and caesium salts show only one phase transition. A phase change, though only at pressures far above 42 kbar, is indicated also for the calcium, the barium and probably the anhydrous lithium salt. The various spectral responses to changes in pressure strongly indicate that in the form prevailing at ordinary pressure and temperature, phase I, the formates of sodium and potassium have the same type of molecular packing in the crystal structure. Phases II of the sodium and potassium salt appear to belong to a new modification (?C?), whereas phase III of the sodium and phase II of the caesium salt belong to the modification ?B? previously observed in disc spectra. In a given phase, the effect of pressure on the formate vibration frequencies is sometimes quite different for the pure crystalline salt in bulk and for the same species when isolated by isotopic dilution. In these cases the main effect of pressure is that on the intermolecular coupling of vibrations. Several frequency changes accompanying phase transitions, by contrast, are essentially unchanged on isotopic dilution and arise mainly from changes in the effective intramolecular force constants.

Effect of Pressure on the Infrared Spectra of Some Hydrogen‐Bonded Solids

1964 ◽  
Vol 41 (1) ◽  
pp. 47-50 ◽  
Author(s):  
Joseph Reynolds ◽  
Sanford S. Sternstein
Keyword(s):  
Infrared Spectra ◽  
Effect Of Pressure ◽  
Hydrogen Bonded

Infrared spectra of some acetylides of lithium, sodium, and potassium

1965 ◽  
Vol 14 (1) ◽  
pp. 37-40 ◽  
Author(s):  
A. N. Rodionov ◽  
G. V. Timofeyuk ◽  
T. V. Talalaeva ◽  
D. N. Shigorin ◽  
K. A. Kocheshkov
Keyword(s):  
Infrared Spectra ◽  
Sodium And Potassium

Infrared spectra of sodium and potassium fluorides by matrix isolation

1973 ◽  
Vol 35 (9) ◽  
pp. 3201-3206 ◽  
Author(s):  
Zakya K. Ismail ◽  
Robert H. Hauge ◽  
John L. Margrave
Keyword(s):  
Infrared Spectra ◽  
Matrix Isolation ◽  
Sodium And Potassium

Effect of pressure on phase transitions in K1−xNaxMnF3(x = 0.04)

1999 ◽  
Vol 32 (2) ◽  
pp. 174-177 ◽  
Author(s):  
S. Åsbrink ◽  
A. Waśkowska ◽  
H. G. Krane ◽  
L. Gerward ◽  
J. Staun Olsen
Keyword(s):  
Phase Transition ◽  
Parent Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Pressure ◽  
Cell Dimensions ◽  
Main Effect ◽  
Diamond Anvil ◽  
Na Ions ◽  
Unit Cell Dimensions

The pressure-induced phase transition sequence in the title compound, potassium sodium fluoromanganate, has been investigated by single-crystal X-ray diffraction using synchrotron radiation and a diamond anvil pressure cell. Na^+ ions at 4% of the K^+ sites shift the ferrodistortive phase transition to the lower pressure P_{c1} of 2.75 (5) GPa compared to 3.12 GPa in the parent compound KMnF3. The transition is illustrated by the critical behaviour of the unit-cell dimensions, the pressure-dependent evolution of the MnF_6 ^- octahedral rotation and related macroscopic spontaneous strain. As far as precision of the present experiment allows, the observations show that the 4% of Na^+ admixture at the K^+ sites does not substantially change the nature of the transition at P_{c1}. The main effect of pressure is to stabilize the tetragonal phase II. The expected further evolution of the MnF_6 ^- octahedral tiltings, leading to the orthorhombic and monoclinic phases, has not been observed up to 8.33 GPa.

Infrared Spectra of the Alkali Metal Cyanides in the Solid State

1973 ◽  
Vol 27 (2) ◽  
pp. 93-94 ◽  
Author(s):  
Zakya K. Ismail ◽  
Robert H. Hauge ◽  
John L. Margrave
Keyword(s):  
Solid State ◽  
Alkali Metal ◽  
Liquid Nitrogen ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Solid Phase ◽  
Liquid Nitrogen Temperature ◽  
Metal Cyanides ◽  
Sodium And Potassium

The infrared spectra of lithium isocyanide and of sodium and potassium cyanides in the solid phase were examined over the range 4000 to 140 cm−1 at room temperature. A study of the effect of cooling the solids to liquid nitrogen temperature has been carried out.

Structure and Bonding of Tribromocadmates, ACdBr3, A = NH4, Rb, Cs, CH3NH3, (CH3)2NH2, (CH3)4N], [H2NNH3, and (H2N)3C. An X-ray Diffraction and 79-81Br NQR Study

1991 ◽  
Vol 46 (12) ◽  
pp. 1063-1082 ◽  
Author(s):  
V. G. Krishnan ◽  
Shi-qi Dou ◽  
Alarich Weiss
Keyword(s):  
Room Temperature ◽  
High Temperature Phase ◽  
Phase Iii ◽  
Line Spectrum ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Single Chain ◽  
Double Chain ◽  
81Br Nqr ◽  
A Chain

Abstract The 79-81Br NQR spectra of tribromocadmates with the cations K⊕, NH4⊕, Rb⊕, Cs⊕, CH3NH3⊕, (CH3)2NH2⊕, (CH3)4N⊕, H2NNH3⊕, and C(NH2)3⊕ were studied as functions of temperature from 77 K on up to T>300 K. CsCdBr3 shows a singlet 81Br NQR spectrum over the whole temperature range studied. [CH3NH3]CdBr3, with one 81Br NQR line spectrum at room temperature, experiences a phase transition at 167 K; below this temperature an 18-line spectrum is observed. In [(CH3)4N]CdBr3 (phase II), at 290 K, a singlet 81Br NQR is present as is in the high temperature phase III (TII.1 , = 390 K); the low temperature phase III (TII,m, = 160 K has a triplet 81Br NQR spectrum. KCdBr3 shows an 81Br NQR doublet spectrum, as do RbCdBr3, [H2NNH3]CdBr3, and [C(NH2)3]CdBr3. 81Br NQR triplets are observed for [(CH3)2NH2]CdBr3 and NH4CdBr3. Several crystal structures were determined (at room temperature). [(CH3)4N]CdBr3: P63/m, Z = 2, a - 940 pm, c = 700 pm, disordered cation, single chain Perovskite with face connected [CdBr6]- octahedra (nearly CsNiCl3-type). [(CH3)2NH2]CdBr3: P21/c, Z = 4, a = 898 pm, 6 = 1377 pm, c = 698 pm, ß = 91.2°, face connected [CdBr3-octahedra single chain Perovskite. NH4CdBr3: Pnma, Z = 4, a = 950 pm, b = 417 pm, c= 1557 pm, with a double chain of condensed [CdBr6]-octahedra, NH4CdCl3-type. [N2H5]CdBr3: P2,/c, Z = 4, a = 395 pm, 6 = 1749 pm,c = 997 pm,ß = 94.2°, double chain polyanion similar to NH4CdBr3. [C(NH2)3]CdBr3: C2/c, Z = 4, a = 778 pm, 6 = 1598 pm, c = 746 pm, ß = 110.2°, a single chain Perovskite with a chain of condensed trigonal bipyramids [CdBr5]. Three types of anion chains of CdBr3 have been observed: Single octahedral chains, face connected; double octahedral chains, edge connected; a trigonal-bipyramidal chain, edge connected. The relation between the crystal structure and the Br NQR is discussed

Vibrational spectroscopy of semiheavy water (HDO) as a probe of solute hydration

2010 ◽  
Vol 82 (10) ◽  
pp. 1869-1887 ◽  
Author(s):  
Maciej Śmiechowski ◽  
Janusz Stangret
Keyword(s):  
Spectral Analysis ◽  
Vibrational Spectroscopy ◽  
Infrared Spectra ◽  
Isotopic Dilution ◽  
Vibrational Modes ◽  
Analysis Method ◽  
Dilution Technique ◽  
Difference Spectra ◽  
Quantitative Version ◽  
The Difference

Vibrational spectroscopy is an ideally suited tool for the study of solute hydration. Nevertheless, water is commonly considered by spectroscopists a difficult solvent to work with. However, by using the isotopic dilution technique, in which a small amount of D2O is introduced into H2O or vice versa with formation of semiheavy water (HDO), many technical and interpretative problems connected with measurement of infrared spectra of water may be circumvented. Particularly, the isotopic decoupling of stretching vibrational modes greatly simplifies interpretation of the spectra. Systematic studies conducted in several laboratories since the 1980s up to the present day have provided a vast amount of data, concerning mainly ionic hydration. Many of these experiments have been performed in our laboratory. The analysis method we applied is based on the quantitative version of the difference spectra technique and allows separation of the spectrum of solute-affected HDO from the bulk solvent. This review illustrates the development of vibrational spectroscopy of HDO and spectral analysis methods over the years, as well as summarizes the results obtained for ionic and nonionic solutes, including some general hydration models formulated on their basis.

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