Frequencies, anharmonicities, and dissociation energies of OH groups in H-mordenite

Harmonic frequencies, anharmonicities and dissociation energies of surface hydroxy groups in H-mordenite have been determined. The application of the Lippincott-Schroeder potential function for similar problems is proposed.

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, -. - .

     

M Spectra of the Rare Earth Elements Measured with an Ultra-Thin Window Si(Li) Detector

The oxides of the rare earth elements 57Z71 were excited by electrons with an energy between 3 and 15keV. X-rays were detected by an energy dispersive Si(Li) spectrometer, with an ultra-thin polymer entrance window. Due to the limited resolution of this type of spectrometer, the M spectra of the rare earths appear to consist of only four peaks: M, M,, M, and M₂N₄. The net height of these peaks relative to that of M, was used as a measure of the relative intensity. For 3keV electrons, a continuous decrease of the relative intensity of M with increasing Z was observed, ranging from approximately 90% for 57 La to less than 10% for 71 Lu. This behaviour is in agreement with a model involving a gradual filling up of the levels N6 and N7 with increasing Z. The relative intensity of M is lower than that of M by about a factor of 5, whereas M₂N₄ is approximately half as intense as M.     

α,β-Butenolides

,-Dibromo--('-carbethoxyacetony)-^,-butenolide (I) reacts with amines in diethyl ether solution to give -bromo-amino--('-carbethoxyacetony)-^,-butenolides. Compounds n are converted to -bromo-amino--('-carbethoxyacetony)-^,-butenolides on reaction with amines. The corresponding arylhydrazones (VI and VII) are obtained by the reaction of I and II with p-nitro- and 2,4-dinitrophenylhydrazines. Compound I reacts with phenylhydrazine to give furopyridazine VIII.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–871, July, 1972.     

Alkali hexamolybdochromates

Li, Na, K, Rb, Cs and NH₄ hexamolybdochromates have been prepared, characterized by X-ray and IR spectra, and their thermal behaviour was studied. We observed that the anion decomposition occurs only when the last 3 H₂O are eliminated. TheH values for this elimination decrease from the Li to the Cs salt in the same manner as the lattice energies found in other alkali salts with a common anion. The exothermic reactions in the decomposition of the complexes are interpreted by inspection of the compounds obtained.

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Zusammenfassung Die dargestellten Hexamolybdochromate von Li, Na, K, Rb, Cs und NH₄ wurden durch ihre Röntgen- und Infrarotspektren charakterisiert und ihr thermisches Verhalten studiert. Die Zersetzung des Anions begann erst nach Entweichen der letzten 3 H₂O. DieH-Werte dieses Vorganges sinken in derselben Weise vom Li zum Cs wie die Gitterenergien anderer Alkalisalze mit gleichem Anion. Die auf die Zersetzung folgenden exothermischen Reaktionen wurden durch Untersuchung der erhaltenen Verbindungen gedeutet.

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Résumé Examen du comportement thermique des hexamolybdochromates de Li, Na, K, Rb, Cs et NH₄ caraetérisés par leurs spectres de rayons X et infrarouges. La décomposition de l'anion ne commence qu'après l'élimination des 3 dernières molécules d'eau. Les valeursH de ce processus décroissent du sel de lithium à celui de césium de la même manière que les valeurs des énergies de réseau d'autres sels alcalins contenant le même anion. Interprétation des réactions exothermiques relatives à la décomposition des complexes par examen des composés obtenus.

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Li, Na, K, Rb, Cs NH₄, - , . , 3 H₂O. H Li- Cs- , , . , , .

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This work was supported by Consiglio Nazionale delle Ricerche.     

A new improved expression for gamma-ray detection efficiency of Ge(Li) detectors

In the present paper, a new improved expression for -ray detection efficiency of Ge(Li) detectors, ⁰ , is given. It is represented as a continuous function of x (viz. E ^–1) with a maximum and decreases very rapidly to a small positive value as -ray energy, E, drops to 40 keV or lower, but slowly as E rises to 1.7 MeV or higher. Since it can well represent the whole physical process of the -ray detection, this expression may be one of the simplest and most precise representations, for ⁰ at the present time.     

Solvent effects on chemical processes. 4. Complex formation between naphthalene and theophylline in binary aqueous-organic solvents

The standard free energy change for complex formation is written as a sum of effects arising from solvent-solvent interactions (the general medium effect), solvent-solute interactions (the solvation effect), and solute-solute interactions (the intersolute effect). The general medium effect is given by gA(–_o), where g is a curvature correction factor to the solvent surface tension , A is the change in surface area as the two solvent cavities containing the substrate (naphthalene) and ligand (theophylline) collapse into a single cavity containing the complex, and _o is the value of surface tcnsion at which there is no net solvophobic interaction; is defined to be the value appropriate to the equilibrium mean solvation shell composition. The solvation effect is modeled by equilibrium stoichiometric formation of solvated species. All data are related to the fully aqueous system to give _MG^o, the solvent effect on the free energy change, as an explicit function of solvent composition. Solvent effects on bimolecular association are related to solvent effects on the solubilities of the substrate, ligand, and complex. Approximation methods for interpreting such systems are described and are applied to the naphthalene-theophylline complex. It is shown that complex destabilization in mixed aqueous-organic solvents (relative to the fully aqueous system) may receive contributions from both the general medium and the solvation effects, and that these contributions can be quantitatively estimated.     

INDO study of the interaction of methanol with molybdates

The energy of interaction between a methanol molecule and an MoO ₄ ^2– group of the Fe₂(MoO₄)₃ and Ga₂(MoO₄)₃ lattice, and the force constant of the C–H bond calculated by the INDO method show that the deformation of MoO ₄ ^2– tetrahedra leading to the displacement of Mo⁶⁺ to the edge attacked, increase the stabilizing contribution to the energy and decrease the C–H force constant. This effect is maximal at 1_Mo–O2 Å.

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INDO MoO ₄ ^2– , - Fe(MoO₄)₃ Ga₂(MoO₄)₃ C–H, , MoO ₄ ^2– , Mo⁶⁺ , C–H. 1_Mo–O2 Å.

     

Thermal and X-ray diffraction investigations of vanadium(V) oxide-alkali persulfate binary systems

Thermoanalytical investigations of the V₂O₅-K₂S₂O₈ system have revealed that, in the presence of excess amounts of V₂O₅, the initial decomposition temperature is lowered compared to that of the pure salt. An explanation for this lowering is based on the interaction between V₂O₅ and the peroxo group of the persulfate ion. The reaction however, is, not unimolecular. The presence of an unknown potassium sulfate complex of V(V) with a catalytic character is indicated by XRD patterns obtained for samples heated up to 410°. It has been found that the formation of K₃VO₈, KV(SO₄)₂, K₃V₅O₁₄ and K₄V₁₀O₂₇ depends on whether V₂O₅ or K₂SO₄ is present in excess during thermal decomposition.Sharpd-lines for unknown phases are identified. V₂O₅ is found to behave differently towards sodium and potassium persulfates.Compounds such asa-NaVO₃, NaVO₃, NaV₃O₈ and NaV₆O₁₅ are obtained on thermal analysis of various molar ratios of the V₂O₅- Na₂S₂O₈ system.

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Zusammenfassung Thermoanalytische Untersuchungen des Systems V₂O₅ - K₂S₂O₈ zeigten, daß die Zersetzungstemperatur in Gegenwart überschüssiger Mengen von V₂O₅ im Vergleich zu dem reinen Salz herabgesetzt wird. Eine Erklärung für diese Verminderung beruht auf der Wechselwirkung zwischen V₂O₅ und der Peroxo-Gruppe des Persulfat-Ions. Die Reaktion ist jedoch nicht unimolekular. Die Gegenwart eines unbekannten Kaliumsulfatkomplexes von V(V) mit katalytischen Charakter wird durch die Röntgenbeugung bei bis zu 410° erhitzen Proben angedeutet. Es wurde festgestellt, daß die Bildung von K₃VO₈, KV(SO₄)₂, K₃V₅O₁₄ und K₄V₁₀O₂₇ davon abhängt, ob während der thermischen Zersetzung V₂O₅ oder K₂SO₄ im Überschuss vorhanden ist. Scharfed-Linien wurden für die unbekannten Phasen identifiziert. Es wurde gefunden, daß sich V₂O₅ gegenüber den Persulfaten von Natrium und Kalium unterschiedlich verhält. Verbindungen wiea-NaVO₃, NaVO₃, NaV₃O₈ und NaV₆O₁₅ werden bei der thermischen Analyse verschiedener Molverhältnisse des V₂O₅ - Na₂S₂O₈-Systems erhalten.

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Résumé L'étude thermoanalytique du système V₂O6 - K₂S₂O₈ montre que la température initiale de la décomposition diminue en présence d'un excès de V₂O₅. Une explication de cette diminution repose sur l'interaction de V₂O₅ avec le groupe peroxo de l'ion persulfate. Cependant, la réaction n'est pas unimoléculaire. Les clichés XRD obtenus avec des échantillons chauffés à 410° indiquent la présence d'un complexe inconnu de sulfate de potassium avec V(V) de caractère catalytique. On a trouvé que la formation de K₃VO₈, KV(SO₄)₂, K₃V₅O₁₄ et K₄V₁₀O₂₇ dépend de la présence d'un excès de V₂O₅ ou K₂SO₄ pendant l'analyse thermique. On a identifié des raiesd nettes pour les phases inconnues. On a trouvé que V₂O₅ se comporte de façon différente vis-à-vis de sulfates de potassium et de sodium. Des composés tels que:a-NaVO₃, NaVO₃) NaV₃O₈ et NaV₆O₁₅ ont été obtenus lors de l'analyse thermique du système V₂O₅ - Na₂S₂O₈ avec divers rapports molaires.

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V₂O₅-K₂S₂O₈ , V₂O₅ . V₂O₂ . . 410° - (), . , K₃VO₈, KV(SO₄)₂, K₃V₅O₁₄ K₄V₁₀O₂₇ , V₂O₅ K₂SO₄ . d- . . V₂O₅-N₂S₂₈ a-NaVO₃, NaVO₃, NaV₃O₈ NaV₆O₁₅.

     

TLC technique for the detection and determination of gamma- BHC in biological material

Summary Five isomers present in technical benzene hexachloride were successfully separated by TLC on silica-gel G impregnated with silver nitrate solution. The -isomer was identified by running a control sample of -BHC. Measurement of the spot area was found suitable for the estimation of 5–20g of-BHC, and was applied to analysis of autopsy tissues. The limit of identification is 0.1g.

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Zusammenfassung Auf mit Silbernitratlösung imprägniertem Kieselgel G konnten dünn-schichtchromatographisch fünf Isomere aus technischem Hexachlorbenzol erfolgreich getrennt werden. Das-Isomere wurde mit Hilfe einer Vergleichsprobe identifiziert. Die Planimetrie der Flecken eignet sich zur Schätzung von 5–20 g-Hexachlorbenzol. Die Methode wurde zur Untersuchung von Autopsieproben angewendet. Die Nachweisgrenze beträgt 0,1g.

     

Dimerization of N-methylanabasine in the presence of metallic sodium

In a study of the dimerization of N-methylanabasine in the presence of metallic sodium under conditions for the dimerization of pyridine, it was found that the reaction does not take place at room temperature while at 50–70° C it leads to the formation of,-di(1-methylpiperid-2-yl)-,-bipyridyl. Oxidation of the latter yielded 4,4-bipyridyl-5, 5-dicarboxylic acid, the decarboxylation of which gave,-bipyridyl.