Infrared spectra of the ammonium ion in crystals. Part VIII. Spectroscopic criteria of highly-bent hydrogen bonds

1980 ◽  
Vol 58 (9) ◽  
pp. 867-874 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk
Keyword(s):  
Low Temperature ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Ammonium Ion ◽  
Temperature Transition ◽  
Increasing Temperature

Available evidence suggests that (1) the stretching frequencies of highly-bent hydrogen bonds decrease with increasing temperature, regardless of whether the bonds are static or dynamic in character, to a single acceptor or to several competing acceptors; and (2) departures from symmetric trifurcation (or bifurcation) toward asymmetric situations lower the stretching frequency. In further support of these criteria isotopic probe ion spectra between 10 K and room temperature have been obtained for taurine and for trigonal (NH4)2MF6 (M = Si, Ge, Sn, Ti). Evidence of a low-temperature transition at 100(10) K in trigonal (NH4)2SnF6 is presented, and existence of the previously reported transition at 38.6 K in trigonal (NH4)2SiF6 is confirmed. Symmetry changes associated with these transitions are discussed.

Infrared spectra of the ammonium ion in crystals. Part XIV. Hydrogen bonding and orientation of the ammonium ion in fluorides, with observations on the transition temperatures in cubic cryolite, elpasolite, and perovskite halides

1985 ◽  
Vol 63 (12) ◽  
pp. 3328-3353 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk ◽  
Werner Massa
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Halogen Atom ◽  
Ammonium Ion ◽  
Transition Temperatures ◽  
Coordination Numbers ◽  
Geometric Tolerance ◽  
Ionic Size

The ir spectra of the isotopic probe ion NH3D+ have been used to obtain information about the symmetry, orientation, and hydrogen-bonding involvement of the ammonium ion, between 10 K and room temperature, in NH4F, NH4HF2, (NH4)2[Cr(H2O)6]F5, NH4PF6, (NH4)3SiF7, the elpasolites (NH4)2BFeF6 (B = Na, K) and CS2NH4MF6 (M = Fe, Al), and the cryolites (NH4)3MF6 (M = Al, Cr, Fe). Several of these fluorides exhibit low-temperature transitions, some of which are evident in the probe-ion spectra. It is shown that relating the isotopically isolated ND stretching and bending frequencies to the [Formula: see text] distances and to the coordination numbers of the ammonium ion reveals important trends in the dependence of the behaviour of the ion on its immediate environment in the crystal. A detailed discussion is presented of the effect of ionic size and the geometric tolerance factor t on the transition temperatures of cubic cryolite, perovskite, and elpasolite halides, as well as on the anisotropy of the principal thermal amplitudes of the halogen atom in such compounds. The relation between Ttr and the frequency of the ND stretching absorption of NH3D+ in the ammonium representatives of these classes of halides is also explored.

Transition Insulator-Metal and Antiferromagnetic-Paramagnetic Cu Doped in La0.47Ca0.53MnO3

2015 ◽  
Vol 1123 ◽  
pp. 73-77 ◽  
Author(s):  
Yohanes Edi Gunanto ◽  
K. Sinaga ◽  
B. Kurniawan ◽  
S. Poertadji ◽  
H. Tanaka ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Temperature ◽  
Magnetic Structure ◽  
Room Temperature ◽  
Paramagnetic Phase ◽  
Perovskite Manganites ◽  
Antiferromagnetic Phase ◽  
Temperature Transition ◽  
Cu Doping ◽  
Metal State

The study of the perovskite manganites La0.47Ca0.53Mn1-xCuxO3 with x = 0, 0.06, 0.09, and 0.13 has been done. The magnetic structure was determined using high-resolution neutron scattering at room temperature and low temperature. All samples were paramagnetic at room temperature and antiferromagnetic at low temperature. Using the SQUID Quantum Design, the samples showed that the doping of the insulating antiferromagnetic phase La0.47Ca0.53MnO3 with Cu doping resulted in the temperature transition from an insulator to metal state, and an antiferromagnetic to paramagnetic phase. The temperature transition from an insulator to metal state ranged from 23 to 100 K and from 200 to 230 K for the transition from an antiferromagnetic to paramagnetic phase.

The role of hydrogen bonds in order-disorder transition of a new incommensurate low temperature phase β-[Zn-(C7H4NO4)2]·3H2O

2018 ◽  
Vol 233 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Masoumeh Tabatabaee ◽  
Morgane Poupon ◽  
Václav Eigner ◽  
Přemysl Vaněk ◽  
Michal Dušek
Keyword(s):  
Low Temperature ◽  
Hydrogen Bonds ◽  
Dicarboxylic Acid ◽  
Room Temperature ◽  
Temperature Phase ◽  
Temperature Structure ◽  
Modulated Structure ◽  
Q Vector ◽  
Low Temperature Phase

AbstractThe room temperature structure withP21/csymmetry of the zinc(II) complex of pyridine-2,6-dicarboxylic acid was published by Okabe and Oya (N. Okabe, N. Oya, Copper(II) and zinc(II) complexes of pyridine-2,6-dicarboxylic acid.Acta Crystallogr. C.2000,56, 305). Here we report crystal structure of the low temperature phaseβ-[Zn(pydcH)2]·3H2O, pydc=C7H3NO4, resulting from the phase transition around 200K. The diffraction pattern of the low temperature phase revealed satellite reflections, which could be indexed with q-vector 0.4051(10)b* corresponding to (3+1)Dincommensurately modulated structure. The modulated structure was solved in the superspace groupX21/c(0b0)s0, whereXstands for a non-standard centring vector (½, 0, 0, ½), and compared with the room temperature phase. It is shown that hydrogen bonds are the main driving force of modulation.

81Br NQR and Crystal Structure of Ethylammonium Tribromomercurate(II), CH3CH2NH3HgBr3

1994 ◽  
Vol 49 (1-2) ◽  
pp. 202-208 ◽  
Author(s):  
Hiromitsu Terao ◽  
Tsutomu Okuda ◽  
Kichiro Koto ◽  
Shi-qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
High Temperatures ◽  
Title Compound ◽  
Room Temperature ◽  
Mercury Atom ◽  
Double Chain ◽  
Trigonal Bipyramidal ◽  
81Br Nqr ◽  
Increasing Temperature

Abstract The 81Br NQR triplet spectrum of (CH3CH2NH)3⊕(HgBr3)⊖ was measured in the range 77 K to near the m.p. (99~106°C) v1 decreases strongly with increasing temperature, exhibiting 136.784 MHz at 77 K and 128.129 MHz at 298 K. v2 decreases from 82.060 MHz at 77 K to 76.322 MHz at 298 K. v3 increases with temperature, showing v3 = 81.292 MHz at 77 K and 84.903 MHz at 298 K. Replacement of the ammonium hydrogens by deuterium produces a negative shift of v1 and positive ones of v2 and v3 at high temperatures. These shifts change with temperature from |~ 0| up to |~ 200| kHz. The crystal structure of the title compound was determined at room temperature: P 21/m, Z = 2, a = 1021.6(8) pm, b = 643.0(6) pm, c = 691.8(6) pm, β = 96.96 (4)°. The coordination of the mercury atom by the bromines is trigonal bipyramidal; by formation of bridges Hg··· Br··· Hg by one of the three bromines (Br(2)) of the planar HgBr⊖ ions a double chain of trigonal bipyramids is formed, running along the b-axis of the crystal. Br(1) and Br(3) are single bonded to Hg. The hydrogen bonds N -H···Br(1) and N -H ··· Br(3) (twice), connect the Hg-Br chains to planes lying parallel to the be plane at x = 0. The relations between the Br-NQR spectrum and the structure are discussed.

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

Infrared spectra of the ammonium ion in crystals. Part XIII. Crystal structure of (NH4)2[AlF5(H2O)] and NH3D+ probe-ion spectra in (NH4)2[AlF5(H2O)], NH4AlF4, and (NH4)3ZnCl5, with remarks on structural filiation of AMF4 fluorides

1985 ◽  
Vol 63 (2) ◽  
pp. 516-525 ◽  
Author(s):  
Osvald Knop ◽  
T. Stanley Cameron ◽  
S. P. Deraniyagala ◽  
D. Adhikesavalu ◽  
Michael Falk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
The Other ◽  
Ammonium Ion ◽  
Colour Space ◽  
Low Frequencies ◽  
Space Groups ◽  
Disordered Phase ◽  
Normal Formula

The crystal structure of (NH4)2AlF5•H2O = (NH4)2[AlF5(H2O)] (Pbcn, a = 10.192(4) Å, b = 8.037(2) Å, c = 7.844(1) Å, Z = 4) consists of isolated [AlF5(H2O)]2− octahedral and NH4+ ions. The octahedra are linked by [Formula: see text] bonds to form zigzag chains parallel to c and the chains are cross-linked by normal [Formula: see text] hydrogen bonds to the NH4+ ions. The ir characteristics of the hydrogen bonds in this and the other two title compounds were probed with the NH3D+ ion between 10 and 293 K. The probe-ion spectra confirm the C1 symmetry of the ammonium ion in (NH4)2[AlF5(H2O)] and point to [Formula: see text] bonding of moderate strength. For NH4AlF4 the spectra agree with the expectation from the known crystal structure of both the ordered and the disordered phase, but the transition at ~150 K is not evident in the evolution of the spectra with temperature. Detailed assignment of the ND stretching and bending component absorptions of NH3D+ is not possible for (NH4)3ZnCl5 = (NH4)3(ZnCl4)Cl. However, the unusually low frequencies of two of the components of the ND stretching absorptions in this crystal indicate the existence of [Formula: see text] bonds stronger than those in NH4Cl. The filiation of the known AMF4 structures deriving from TlAlF4 is presented in terms of two-colour space groups.

scholarly journals TheZ′ = 12 superstructure of Λ-cobalt(III) sepulchrate trinitrate governed by C—H...O hydrogen bonds

2016 ◽  
Vol 72 (3) ◽  
pp. 372-380 ◽  
Author(s):  
Somnath Dey ◽  
Andreas Schönleber ◽  
Swastik Mondal ◽  
Siriyara Jagannatha Prathapa ◽  
Sander van Smaalen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Structural Parameters ◽  
Molecular Packing ◽  
Nitrate Group ◽  
Structural Variations ◽  
Monoclinic Symmetry ◽  
Low Temperature Crystal Structure

Λ-Cobalt(III) sepulchrate trinitrate crystallizes inP6322 withZ= 2 (Z′ = 1/6) at room temperature. Slabs perpendicular to the hexagonal axis comprise molecules Co(sepulchrate) alternating with nitrate groupsAandB. Coordinated by six sepulchrate molecules, highly disordered nitrate groupsCare accommodated between the slabs. Here we report the fully ordered, low-temperature crystal structure of Co(sep)(NO3)3. It is found to be a high-Z′ structure withZ′ = 12 of the 12-fold 6a_{h}\times\sqrt{3}b_{h}\times c_{h} superstructure with monoclinic symmetryP21(cunique). Correlations between structural parameters are effectively removed by refinements within the superspace approach. Superstructure formation is governed by a densification of the packing in conjunction with ordering of nitrate groupC, the latter assuming different orientations for each of theZ′ = 12 independent copies in the superstructure. The Co(sep) moiety exhibits small structural variations over its 12 independent copies, while orientations of nitrate groupsAandBvary less than the orientations of the nitrate groupCdo. Molecular packing in the superstructure is found to be determined by short C—H...H—C contacts, with H...H distances of 2.2–2.3 Å, and by short C—H...O contacts, with H...O distances down to 2.2 Å. These contacts presumably represent weak C—H...O hydrogen bonds, but in any case they prevent further densification of the structure and strengthening of weak N—H...O hydrogen bonds with observed H...O distances of 2.4–2.6 Å.

Erstmalige Charakterisierung der Ammoniak-Proton-Komplexe [(NH3)3H]+ und [(NH3)4H]+ in den Kristallstrukturen von (NH4)3AsS4 · 5 NH3 und (NH4)3SbS4 · 8 NH3 / First Characterization of the Ammonia-Proton-Complexes [(NH3)3H]+ and [(NH3)4H]+ in the Crystal Structures of (NH4)3AsS4 · 5 NH3 and (NH4)3SbS4 · 8 NH3

2003 ◽  
Vol 58 (7) ◽  
pp. 672-677 ◽  
Author(s):  
Thomas Roßmeier ◽  
Nikolaus Korber
Keyword(s):  
Low Temperature ◽  
Ion Exchange ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Liquid Ammonia ◽  
Ammonium Ion ◽  
X Ray ◽  
Exchange Material ◽  
First Time

The compounds (NH4)3AsS4· 5 NH3 (1) and (NH4)3SbS4· 8 NH3 (2) were prepared by the reaction of Na3AsS4 and Na3SbS4 with a proton-charged ion exchange material in liquid ammonia and characterized by low temperature single crystal X-ray structure analysis. The ammonium-ammoniates show H3N-H···N-hydrogen bonds between the ammonium ion and ammonia molecules ranging from 1.86 to 2.55 Å (DHA-angles: 145 - 173°) and H3N-H···S-bonds to the thioanions between 2.36 and 2.97 Å (DHA-angles: 130 - 176°). The former of the interactions are responsible for the formation of [(NH3)2H]+, [(NH3)3H]+ and [(NH3)4H]+-complexes, the last two of which were characterized by X-ray analysis for the first time.

Synthese und Kristallstrukturen von N-[ω-(Dimethylammonio)alkyl]- N´,N´,N´´,N´´-tetramethylguanidinium-chlorid-tetraphenylboraten / Synthesis and Crystal Structures of N-[ω-(Dimethylammonio)alkyl]-N´,N´,N´´,N´´- tetramethylguanidinium Chloride Tetraphenylborates

2010 ◽  
Vol 65 (7) ◽  
pp. 907-916 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Falk Lissner ◽  
Thomas Schleid ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Room Temperature ◽  
Chloride Ions ◽  
Monoclinic Space Group ◽  
Temperature Structure ◽  
Space Group ◽  
Temperature Modification

Dicationic N,N´,N´,N´´,N´´-pentasubstituted guanidinium dichlorides 4a, b are obtained from the chloroformamidinium salt 2 and diamines 3a, b. N-[2-(Dimethylammonio)ethyl]-N´,N´,N´´,N´´-tetramethylguanidinium chloride tetraphenylborate (5a) and N-[3-(dimethylammonio)propyl]-N´,N´,N´´,N´´-tetramethylguanidinium chloride tetraphenylborate (5b) were synthesized from 4a, b by anion metathesis with one equivalent of sodium tetraphenylborate. The thermal properties of the salts 5a, b were studied by means of DSC methods, and their crystal structures were determined by single-crystal X-ray diffraction analysis. For 5a a solid-solid phase transition is observed at −156 ◦C to a low-temperature structure. The room-temperature modification (α-5a) crystallizes in the centrosymmetric orthorhombic space group Pbca (a = 13.1844(4), b = 13.8007(4), c = 34.7537(11) A° ).The guanidinium ions are interconnected via chloride ions through bridging N-H· · ·Cl hydrogen bonds, providing isolated units. The tetraphenylborate ions show some dynamic disordering in the crystal structure. The low-temperature modification (β -5a) also crystallizes orthorhombically, but in the non-centrosymmetric space group Pna21 (a = 13.1099(4), b = 69.1810(11), c = 13.5847(5) A° ) and consists of four crystallographically independent cations and anions in the unit cell. Compared with the room-temperature structure, a similar N-H· · ·Cl hydrogen bond pattern is observed in the β -phase, but the tetraphenylborate ions are now completely ordered. 5b crystallizes in the monoclinic space group P21/c (a = 10.8010(3), b = 14.1502(5), c = 20.9867(9) A° , β = 94.322(1)◦). In the crystal structure the guanidinium ions are linked via chloride ions through N-H· · ·Cl hydrogen bonds, but in contrast to 5a two infinite strands are formed along the a axis with the tetraphenylborate ions interspersed between them for charge compensation.

Low-temperature raman study on ThSiO4 single crystal and related infrared spectra at room temperature

1986 ◽  
Vol 64 (2) ◽  
pp. 181-187 ◽  
Author(s):  
M.P. Lahalle ◽  
J.C. Krupa ◽  
M. Lepostollec ◽  
J.P. Forgerit
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Raman Study
Sign in / Sign up

Export Citation Format

Share Document