Bis(triethylammonium) hexachlorostannate (IV): crystal structure and hydrogen bonding

1981 ◽  
Vol 59 (16) ◽  
pp. 2550-2555 ◽  
Author(s):  
Osvald Knop ◽  
T. Stanley Cameron ◽  
Margaret Ann James ◽  
Michael Falk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Fermi Resonance ◽  
Ammonium Compound ◽  
Compound A ◽  
Stretching Vibration ◽  
Cl Atoms

The crystal structure of (Et3NH)2SnCl6 at room temperature consists of a monoclinically distorted antifluorite packing of Et3NH+ and SnCl62− ions. Each anion has two cations centrosymmetrically associated with it through bifurcated hydrogen bonds to four of the Cl atoms, leaving two of the six chlorines unengaged. The bifurcation is nearly symmetric and the [Formula: see text] group is nearly planar. Infrared spectra of undeuterated and partially deuterated polycrystalline (Et3NH)2SnCl6 show that the NH stretching vibration is essentially uncoupled while the corresponding ND vibration undergoes a complex Fermi resonance resulting in a multiplet in the spectrum of even weakly deuterated material. The hydrogen bonding in (Et3NH)2SnCl6 is stronger than in the corresponding ammonium compound. A negative temperature coefficient of the NH and ND stretching frequencies is consistent with the bifurcation of the hydrogen bond. If a low-temperature transition exists, it was not evident in the NH and ND stretching absorptions.

Triethylammonium halides, Et3NHX (X = Cl, Br, I): simple structure, complex spectrum

1985 ◽  
Vol 63 (7) ◽  
pp. 1750-1758 ◽  
Author(s):  
Margaret Ann James ◽  
T. Stanley Cameron ◽  
Osvald Knop ◽  
Murray Neuman ◽  
Michael Falk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Ir Spectra ◽  
Structure Determination ◽  
Room Temperature ◽  
Simple Structure ◽  
Fermi Resonance ◽  
Crystal Structure Determination ◽  
Complex Spectrum ◽  
Resonance Interactions

A crystal structure determination has shown that the ethyl groups in the three isostructural (P63mc, Z = 2) triethylammonium halides, Et3NHX (X = Cl, Br, I), at room temperature are orientationally disordered and the [Formula: see text] groups are linear by symmetry. The unusual extent and complexity of the NH and ND stretching absorptions in the ir spectra of all three compounds between 10 and 293 K are discussed in terms of Fermi resonance interactions. The centroid ν(NH) and ν(ND) frequencies extracted from the spectra correlate with the [Formula: see text] distances. It is shown that if Fermi resonance is the sole cause of the complexity of the stretching absorptions, then these centroids represent the ν(NH) and ν(ND) frequencies unperturbed by Fermi resonance. The centroid frequencies in the three halides are unusually low, pointing to strong [Formula: see text] hydrogen bonding.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

scholarly journals Ferrite-based room temperature negative temperature coefficient printed thermistors

2020 ◽  
Vol 56 (24) ◽  
pp. 1322-1324
Author(s):  
J.R. McGhee ◽  
J.S. Sagu ◽  
D.J. Southee ◽  
P.S.A. Evans ◽  
K.G.U. Wijayantha
Keyword(s):  
Temperature Coefficient ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature

Alkylammonium hexachlorostannates(IV), (RnNH4−n)2SnCl6: crystal structure, infrared spectrum, and hydrogen bonding

1983 ◽  
Vol 61 (7) ◽  
pp. 1620-1646 ◽  
Author(s):  
Osvald Knop ◽  
T. Stanley Cameron ◽  
Margaret Ann James ◽  
Michael Falk
Keyword(s):  
Hydrogen Bonding ◽  
Room Temperature ◽  
Fermi Resonance ◽  
Molecular Volume ◽  
Site Symmetry ◽  
Dilution Technique ◽  
Orientational Disorder ◽  
Anomalous Temperature ◽  
Ammonium Compounds ◽  
Anion Packing

In an effort to advance our understanding of the principles governing the structures of and the hydrogen bonding in alkylammonium hexachlorostannates(IV), (RnNH4−n)2SnCl6, we have determined the room-temperature crystal structures of (Me2NH2)2SnCl6 and (Me3NH)2SnCl6 (variants of the antifluorite structure); (EtNH3)2SnCl6 and (n-PrNH3)2SnCl6 (anti-Cdl2 type, with orientational disorder in the Et compound); and (n-Pr3NH)2SnCl6. We have also studied the infrared spectra in the regions of the NH and ND stretching fundamentals, between 10 and 293 K, of these five compounds and of (MeNH3)2SnCl6, (Me3NH)2SnBr6, (Et2NH2)2SnCl6, (n-Bu3NH)2SnCl6 and, in less detail, the mixed-anion salt (n-Pr2NH2)3(SnCl6)Cl. The spectra are often complicated by Ferim resonance involving absorptions diagnostically critical for the strength and type of [Formula: see text] bonding and for the site symmetry at the N atom. In this respect they are less useful than the corresponding spectra of the unsubstituted ammonium compounds reported previously. Several of the spectra provide striking examples of temperature-tuned Fermi resonance of NH and ND vibrations. The [Formula: see text] bonds are invariably trifurcated, bifurcated, or at least highly bent; these characteristics give rise to anomalous temperature dependence of the frequencies of the NH and ND stretching fundamentals. Temperature-induced transitions were detected in (Me2NH2)2SnCl6 (Ttr ~ 100 K), Et NH3)2SnCl6 (Ttr ~ 125 K), and (Et2NH2)2SnCl6 (Ttr ~ 330 K). The specific results for the ten compounds studied arc discussed in detail. The discussion also includes the limits of usefulness of the isotopisc dilution technique; symmetry aspects of the cation–anion packing in alkylammonium hexahalometallates(IV); symmetries of the arrangements of the SnCl6 octahedra; the geometry of hydrogen bonding in (RnNH4−n)2SnCl6; and the possibility of detection of the presence of hydrogen bonding from molecular volume trends.

scholarly journals Crystal structure of a new hybrid antimony–halide-based compound for possible non-linear optical applications

2015 ◽  
Vol 71 (5) ◽  
pp. 498-501 ◽  
Author(s):  
Tarek Ben Rhaiem ◽  
Habib Boughzala
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Water Molecules ◽  
Inorganic Layer ◽  
Organic Part ◽  
Organic Layers ◽  
Hydrogen Bonding Interactions ◽  
Optical Applications ◽  
Cl Atoms ◽  
Inorganic Layers

The hybrid title compound,catena-poly[[[bis(1,4-diazoniabicyclo[2.2.2]octane) [tetraachloridoantimonate(III)]-μ-chlorido-[tetrachloridoantimonate(III)]-μ-chlorido]] monohydrate], {(C6H14N2)2[Sb2Cl10]·H2O}n, is self-assembled into alternating organic and inorganic layers parallel to thebcplane. The anionic inorganic layer consists of infinite zigzag chains of corner-sharing [SbCl6]3−octahedra running along thebaxis. The organic part is made up of 1,4-diazoniabicyclo[2.2.2]octane dications (dabcoH22+). The water molecules in the structure connect inorganic and organic layers. Hydrogen-bonding interactions between the ammonium groups, water molecules and Cl atoms ensure the structure cohesion.

scholarly journals Crystal structure ofcatena-poly[[chlorido(4,4′-dimethyl-2,2′-bipyridine-κ2N,N′)copper(II)]-μ-chlorido]

2015 ◽  
Vol 71 (6) ◽  
pp. 624-627
Author(s):  
Rafaela Nita ◽  
Jeffrey R. Deschamps ◽  
Scott A. Trammell ◽  
D. Andrew Knight
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Title Compound ◽  
Trigonal Bipyramidal Geometry ◽  
Trigonal Bipyramidal ◽  
Bipyridine Ligand ◽  
Cl Atoms ◽  
Cl Atom ◽  
Distorted Trigonal Bipyramidal

The title compound, [CuCl2(C12H12N2)]n, was obtainedviaa DMSO-mediated dehydration of Cu(4,4′-dimethyl-2,2′-bipyridine)copper(II)·0.25H2O. The central CuIIatom is coordinated in a distorted trigonal–bipyramidal geometry by two N atoms of a chelating 4,4′-dimethyl-2,2′-bipyridine ligand [average Cu—N = 2.03 (3) Å] and three Cl atoms, one terminal with a short Cu—Cl bond of 2.2506 (10) Å, and two symmetry-equivalent and bridging bonds. The bridging Cl atom links the CuIIions into chains parallel to [001]viaone medium and one long Cu—Cl bond [2.3320 (10) and 2.5623 (9) Å]. The structure displays both inter- and intramolecular C—H...Cl hydrogen bonding.

A New Series Of Al-Pd-Based Ordered Icosahedral Quasicrystals And Their Electrical Resistivities

1998 ◽  
Vol 553 ◽  
Author(s):  
R Tamura ◽  
T Asao ◽  
M Tamura ◽  
S Takeuchif ◽  
T Shibuya
Keyword(s):  
Electronic Transport ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Resistivity Ratio ◽  
X Ray ◽  
Resistivity Measurements ◽  
Annealing Temperatures ◽  
Electrical Resistivities ◽  
Icosahedral Quasicrystals

AbstractX-ray measurements on samples of Al-Pd-(Fe,Ru,Os) systems with various annealing temperatures and times have been performed in order to gain insights into formations of icosahedral (I) phases and related approximants and to produce single phases of them. As a result, well ordered I phases have been obtained in Al-Pd-(Ru,Os) systems when annealed at 1000 °C for several hours. Formations of the (1/0-1/0-1/0) and the (2/1-2/1-2/1) approximants have been observed in wide compositional ranges in Al-Pd-(Fe,Ru,Os) and Al-Pd-(Ru,Os) systems, respectively. Electrical resistivity measurements of I phases and related approximants are performed as a function of temperature. The resistivity of I phases at room temperature is as high as that of highly resistive I phases such as Al-Pd-Mn and AI-Cu-(Fe,Ru) systems and the resistivity ratio (P12K/P300K) reaches about 1.5 in Al-Pd-Ru I phases. A negative temperature coefficient of the resistivity is observed in (1/0-1/0-1/0) approximants of Al-Pd-(Fe,Ru) systems, which indicates the electronic transport is quite anomalous even in the lowest approximant of the I phase.

Synthesis and Crystal and Molecular Structure of trans-Dichloro(ethanedial dioximato(1—)-N,N')(ethanedial dioxime-N,N')rhodium(III)

1989 ◽  
Vol 44 (1) ◽  
pp. 5-8
Author(s):  
Michel Mégnamisi-Bélombé
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Room Temperature ◽  
Crystal And Molecular Structure ◽  
Crystallographic Direction ◽  
Monoclinic Space Group ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cl Atoms

Abstract trans-Dichloro(ethanedial-dioximato)(ethanediaI-dioxime)rhodium (III), RhCl2(GH)(GH2), has been synthesized and its structure determined by single crystal X-ray diffraction at room temperature. C4H7Cl2N4O4Rh, Mr = 348.94. monoclinic space group P21/ɑ; a = 10.543(3), b = 8.363(2), c = 11.512(3)Å ; β = 92.79(2)°; V = 1024Å3; Z = 4; Dc = 2.26 Mg m-3. Final Rw = 0.075 for 2035 reflections and 139 parameters. The coordination geometry around Rh is a dis­torted (4+2) octahedron, with four chelating N atoms lying in the equatorial plane and the two Cl atoms in the apical positions. The H atoms of the oxime groups are involved in relatively weak intramolecular O-H-O bridgings, as well as in very strong intermolecular bridgings which extend throughout the crystal structure and propagate nearly parallel to the [101] crystallographic direction.

scholarly journals Development of Auto Thermal Control Device For Space Air - Conditioning

2021 ◽  
pp. 193-204
Author(s):  
Akinde Olusola Kunle ◽  
Maduako Kingsley Obinna ◽  
Akande, Kunle Akinyinka ◽  
Adeaga Oyetunde Adeoye
Keyword(s):  
Temperature Coefficient ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Thermal Control ◽  
Positive Temperature Coefficient ◽  
Control Device ◽  
Thermal Source ◽  
Positive Temperature ◽  
Ntc Thermistor

Auto Thermal Control device is an electronic based device which employs the application of temperature sensors to controlling household appliances without human interference directly. In this work, thermal source is used to regulate electrical fan and room heater depending on ambient temperature. The room heater, which is adjusted to a set temperature, switches ‘ON’ when the temperature of a room is low (cold). While the same is switches ‘OFF’ with increase in the room temperature. This triggers ‘ON’ an electric fan at different speeds, and thus cools the room. A temperature sensor, tthermistor, monitors change in room temperature. Two types of thermistor exists: Positive Temperature Coefficient, PTC. An increasee in the resistance of PTC results in increasee in temperature). In the Negative Temperature Coefficient, NTC; a decreasee in resistance yields to temperature increase. This article explored a NTC thermistor. The design could be a ready product in the market of the developing nation where environmental automation is yet fully deployed.

EFFECT OF CURING TEMPERATURE OF EPOXY RESIN ON THE ELECTRICAL RESPONSE OF CARBON NANOTUBE YARN MONOFILAMENT COMPOSITES

2021 ◽  
Author(s):  
OMAR RODRIGUEZ-UICAB ◽  
JANDRO L. ABOT ◽  
FRANCIS AVILÉS
Keyword(s):  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Electrical Resistance ◽  
Epoxy Resins ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Electrical Response ◽  
Negative Temperature ◽  
Curing Temperature ◽  
Temperature Coefficient Of Resistance

The cyclic thermoresistive response of individual carbon nanotube yarns (CNTYs) embedded into epoxy resins is investigated. The influence of the temperature at which the epoxy resin cures on the thermoresistive response is investigated by using two epoxy resins, one that cures at room temperature and the other one that cures at 130 °C. Heating-cooling cycles ranging from room temperature (RT, 25 °C) to 80 °C, incremental cycles (RT to 40 °C, RT to 60 °C and RT to 80 °C) and incremental heating-dwell cycles are applied to monofilament composites, while their electrical resistance is simultaneously recorded. The monofilament composites showed a negative temperature coefficient of resistance during the heating-cooling cycles of -7.07x10-4 °C-1 for specimens cured at high temperature, and -5.93x10-4 °C-1 for specimens cured at room temperature. The hysteresis after the different heating-cooling cycles was slightly smaller for specimens cured at 130 °C, in comparison to specimens cured at room temperature. Several factors including the intrinsic thermoresistivity of CNTY, level of infiltration and the effect of curing temperature may explain the thermoresistive sensitivity of the monofilament composites.

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