RbClO4 Research Articles

Alkali metal ion effect on the photochromism of 1,2-bis(2,4-dimethylthien-3-yl)-perfluorocyclopentene having benzo-15-crown-5 moieties

The photocyclization quantum yield of 1,2-bis(2,4-dimethylthien-3-yl)perfluorocyclopentene having two benzo-15-crown-5 ethers was decreased by the addition of potassium and rubidium perchlorates, and the decrease is ascribed to the increase of the photoinactive parallel conformation ratio by the intramolecular interaction of the two crown ether moieties with a metal ion.

Cation Complexation by Chemically Modified Calixarenes. 11. Complexation and Extraction of Alkali Cations by Calix[5]- and -[6]arene Ketones. Crystal and Molecular Structures of Calix[5]arene Ketones and Na(+) and Rb(+) Complexes.

A series of four calix[5]arenes and three calix[6]arenes (R-calixarene-OCH(2)COR(1)) (R = H or Bu(t)) with alkyl ketone residues (R(1) = Me or Bu(t)) on the lower rim have been synthesized, and their affinity for complexation of alkali cations has been assessed through phase-transfer experiments and stability constant measurements. The conformations of these ketones have been probed by (1)H NMR and X-ray diffraction analysis, and by molecular mechanics calculations. Pentamer 3 (R = R(1) = Bu(t)) possesses a symmetrical cone conformation in solution and a very distorted cone conformation in the solid state. Pentamer 5 (R = H, R(1) = Bu(t)) exists in a distorted 1,2-alternate conformation in the solid state, but in solution two slowly interconverting conformations, one a cone and the other presumed to be 1,2-alternate, can be detected. X-ray structure analysis of the sodium and rubidium perchlorate complexes of 3 reveal the cations deeply encapsulated by the ethereal and carbonyl oxygen atoms in distorted cone conformations which can be accurately reproduced by molecular mechanics calculations. The phase-transfer and stability constant data reveal that the extent of complexation depends on calixarene size and the nature of the alkyl residues adjacent to the ketonic carbonyls with tert-butyl much more efficacious than methyl.

Time-resolved relaxation of one- and two-vibron states in the rubidium perchlorate crystal

The vibrational relaxation times of the ν 2 fundamental mode and the {2ν 2 + ν 1} = [Ω − + Ω +] Fermi doublet of the ClO the rubidium perchlorate crystal are investigated as a function of temperature between 7 and 300 K using high repetition-rate time-resolved picosecond laser techniques. The results show that the neighboring Ω − and Ω + transitions relax predominantly by up-conversion to the higher ν 3 level via scattering of a single lattice phonon, whereas the ν 2 state mainly decays to the relatively more distance upper ν 4 level by scattering of two lattice phonons.

Electrical conduction in ammonium and alkali metal perchlorates

Experimental results on the temperature and frequency dependence of the ac electrical conductivity of rubidium perchlorate (RbP) and cesium perchlorate (CsP) are presented. Studies were carried out in the temperature range from ambient to ∼300 °C and at frequencies ranging from 50 Hz to 1 kHz. Both nominally pure compounds and those doped with CrO42−, SO42−, and Mn2+ were studied. The electrical conduction behavior of these materials is compared with that previously observed in this laboratory for potassium perchlorate (KP) with a view to highlight some common features. Results previously reported in the literature on an analogous material—ammonium perchlorate (AP)—are critically examined in light of the present data. A unified defect-structure model is finally presented. This model emphasizes similarities in the electrical conduction behavior of the above compounds. More importantly, the experimental results on AP seem to be more consistent with this model than with the currently accepted proton transfer mechanism.

ChemInform Abstract: ON THE ANOMALOUSLY LARGE ELECTRICAL CONDUCTIVITY OF AMMONIUM PERCHLORATE‐AMMONIA (1/2)

AbstractBei Zimmertemperatur ist die Wechselstromleitfähigkeit von NH4ClO4 ‐ 2 NH3 etwa l0" mal größer als die von HN4ClO4.

On the anomalously large electrical conductivity of ammonium perchlorate–ammonia (1/2)

A.c. measurements on the diammonia compound of ammonium perchlorate (AP) along with electrical data relating to rubidium perchlorate, its ammonia compound, and liquid ammonia, suggest that the exceptional room temperature conductivity of AP,2NH3 arises from protonic migration.

The decay of 79Sr

A new isotope of strontium has been produced by 64Zn ( 16O, n) 79Sr reaction. The half-life of 79Sr has been accurately determined by milking the rubidium daughter as rubidium perchlorate. The half-life of 79Sr was found to be 8·1 ∓ 0·3 m. Gamma radiation of energies, of 115·7, 166·4, 188·9, 255·7, 444·2, 559·9 and 611·2 KeV are associated with this decay.

The Heats of Solution of Cesium Perchlorate, Rubidium Perchlorate, Rubidium Chlorate, and Lead Phosphate

The Heats of Solution of Cesium Perchlorate, Rubidium Perchlorate, Rubidium Chlorate, and Lead Phosphate

The alkali perchlorates and a new principle concerning the measurements of space-lattice cells

The perchlorates of potassium and ammonium, KCIO 4 and NH 4 CIO 4 , were investigated crystallographically first by Mitscherlich* in the year 1832, then more extensively by Groth in 1868, and later still more fully, in 1907, by T. V. Barker in Oxford, who also included the perchlorates of rubidium and caesium, RbCIO 4 and CsCIO 4 , in his investigations. The scope of all this work, however, only extended to the morphological characters, no optical properties or constants having been dealt with, except as regards some very roughly approximate data given by Groth for the potassium and ammonium salts, which, moreover, in the case of the potassium salt, has proved to be erroneous. The optical investigation of these salts is rendered exceptionally difficult by the fact that only very small crystals can be obtained; especially is this true of the three metallic salts, the largest obtainable crystals rarely reaching the size of a small pin’s head and the most perfectly developed ones being only half that size. The author has long considered it a matter of special importance that the optics of these alkali perchlorates should, if possible, be thoroughly worked out, and recent developments of the X-ray study of crystals, connecting structure with refraction, have rendered this all the more desirable. Such an investigation has, therefore, been attempted, and happily with complete success, although it has proved the most difficult one ever undertaken by the author. For reasons which will be clear from what follows, a complete remeasurement of the crystals of all four salts has also been made, with most satisfactory confirmation of the results of Barker, and extension of them to further important angles and a new “ setting.” The densities of the crystals as determined by Barker required no revision, as they were obtained, obviously with particular care, by the author’s mode of carrying out the Retgers immersion method, using a mixture of methylene iodide and toluene as the immersion liquid. Three outstanding results arose from the work of Barker. Firstly, it was shown that potassium, rubidium, and cæsium perchlorates form a eutropicallv isomorphous series of orthorhombic salts, resembling in this respect the sulphates and selenates of these same three metals studied by the author, and the alkali permanganates studied by Muthmann.* Secondly, ammonium perchlorate proved to be closely isostructural with rubidium perchlorate, just as the sulphates and selenates of the same two bases had been found to be by the author. Thirdly, Barker showed that these perchlorates and the corresponding per­manganates are isomorphous with the barytes group of orthorhombic minerals, barytes BaSO 4 , celestine SrSO 4 , and anglesite PbSO 4 , and that the morpho­logical constants (unit cell dimensions, as indicated relatively by the topic axial ratios) in the cases of barytes and potassium perchlorate and perman­ganate are so close that overgrowths and parallel growths of the two latter salts are readily formed from their solutions on the crystals of barytes.