Dihydrogen Arsenate Research Articles

Dielectric and ultrasonic measurements in CsH2AsO4

The shear elastic constants ${c}_{44}^{E}$ and ${c}_{66}^{E}$ and both the free and clamped $c$-axis dielectric constant have been measured in the paraelectric phase of single-crystal cesium dihydrogen arsenate. The temperature variation of ${c}_{66}^{E}$ is well described by an elastic Curie expression arising from linear piezoelectric coupling. A 20-K difference between the free and clamped Curie temperatures is obtained from an analysis of the elastic measurements and directly from the $c$-axis dielectric measurements. The $a$-axis dielectric constant, which has been measured between 90 and 300 K, shows antiferroelectric characteristics and exhibits a well-defined first-order discontinuity.

Frequency conversion of Nd:YAG laser radiation in RDA

Frequency doubling and tripling of a Nd:YAG laser has been studied in a rubidium dihydrogen arsenate (RDA) crystal. An overall power conversion efficiency of 34% and 12% has been obtained for doubling and tripling, respectively. Some comparison with rubidium dihydrogen phosphate (RDP) crystal is reported for the generation of the third-harmonic radiation at 3547 Å.

Tunable infrared parametric generation in cesium dihydrogen arsenate

Parametric generation of near infrared coherent light, tunable over the range 854-1410 nm, was obtained in an oscillator using a 3-cm crystal of cesium dihydrogen arsenate (CDA). Pumping was accomplished with 10-ns pulses of 532-nm light from a frequency-doubled Nd:YAG laser. Single-pass parametric gains of the order of 300 were obtained in the crystal. The infrared output pulses typically were 1 ns in duration, with a peak power of approximately 600 kW.

High efficient UV generation at 3472 Å in RDA

The high efficient generation of the second harmonic of ruby laser in rubidium dihydrogen arsenate (RDA) is reported. A peak harmonic power of 52 MW was obtained with a fundamental power of 110 MW. In addition, the temperature variation of the birefringence has been measured to be <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d(n_{2}^{e} - n_{1}^{o})/dT = (9.3 \pm 0.4) \times 10^{-6}\degC^{-1}</tex> .

Raman scattering in antiferroelectric ammonium dihydrogen arsenate

Light scattering measurements of the Raman active modes of vibration in the range 10–4000 cm−1 are reported for the paraelectric phase of NH4H2AsO4 in the temperature range 220–295 K. Through examination of these spectra we have identified the protonic, transverse optic, internal, and O–H–O valence vibrations and determined their symmetries.

ChemInform Abstract: OXYGEN EXCHANGE BETWEEN ARSENATE IONS AND WATER OF CRYSTALLIZATION IN THE COURSE OF HYDRATION AND DEHYDRATION OF DISODIUM HYDROGEN ARSENATE AND SODIUM DIHYDROGEN ARSENATE

AbstractDie Kinetik der Austauschreaktion A wurde untersucht.

Refinement of the crystal structures of ammonium dihydrogen phosphate and ammonium dihydrogen arsenate

Refinement of the crystal structures of ammonium dihydrogen phosphate and ammonium dihydrogen arsenate

Raman spectra of rubidium dihydrogen arsenate in its paraelectric phase

The Raman spectra of RbH 2AsO 4, are presented as a function of temperature for the paraelectric phase and are used to investigate the molecular structure of this phase and to investigate the coupled proton—phonon mode responsible for the onset of the ferroelectric phase.

Oxygen Exchange between Arsenate Ions and Water of Crystallization in the Course of Hydration and Dehydration of Disodium Hydrogen Arsenate and Sodium Dihydrogen Arsenate

Abstract Oxygen exchange between arsenate ions and crystal water in the course of hydration of anhydrous salt with water vapor and subsequent dehydration of the resulting hydrate has been studied with disodium hydrogen arsenate and with sodium dihydrogen arsenate. There is a remarkable difference in the exchange behavior between the anhydrous salt prepared by dehydration in vacuo at room temperature and that prepared at higher temperatures. In the former, the degree of exchange increases with increasing molar ratio of the reactants(arsenate to water), while in the latter, it is independent of the molar ratio. In the exchange reactions of the anhydrous salt prepared at higher temperatures, the number of exchangeable oxygen atoms of an arsenate ion is found to be 0.5 (that is, one atom for two arsenate ions) for disodium hydrogen arsenate, and 4 for sodium dihydrogen arsenate.

Efficient frequency doubler utilizing a cesium dihydrogen arsenate crystal

The results are reported of an investigation of a highly efficient laser frequency doubler utilizing a crystal of cesium dihydrogen arsenate (CDA). The high doubling efficiency is due to the considerable width of the phase-matching curve. This width is greater than for other crystals of the KDP group, which includes CDA. Another advantage of this frequency doubler is the ability to operate under 90° phase-matching conditions, which are achieved by heating the crystal to ~45°C.

A neutron diffraction study of the crystal structure of calcium bis(dihydrogen arsenate), Ca(H2AsO4)2

The crystal structure of Ca(H2AsO4)2 (triclinic, PT, with two formula units per cell) has been refined by single-crystal neutron-diffraction analysis to give an R value of 0.025 over 930 independent neutron reflexions. For the non-hydrogen atoms, bond lengths, angles and thermal parameters agree very closely with the results of a recent X-ray analysis. Difference Fourier syntheses, before and after anisotropic leastsquares refinement of all atomic parameters, enabled the four hydrogen atoms to be located unequivocally. In one anion, two half-hydrogens, located at centres of symme:ry, are believed to be engaged in symmetrical hydrogen bonds, 0(5) . . .0(5 ' )= 2.436 A, 0(8) . . .0(8 ' )= 2.444 /~. By contrast, another hydrogen bond is relatively long (2.875 + 0.002 ,~) and non-linear [angle 0(7). . . H(3)... 0(3')= 150-2 + 0-3°]. The As-O bonds carrying the half hydrogen atoms are 1677 + 0-002 .~ long, intermediate in length between As-O bonds with full hydrogens (1-727 + 0.002/~) and thase with no hydrogen atom attached (1.651 + 0.002 A) (averaged values).

Protonic conduction in potassium dihydrogen arsenate

Protonic conduction in potassium dihydrogen arsenate

Proton-Phonon Coupling in CsH2AsO4and KH2AsO4

We have observed strong anharmonic coupling between the pseudospin "tunneling" mode and an optical mode of ${\ensuremath{\beta}}_{2}$ symmetry in the paraelectric phase of cesium dihydrogen arsenate. At temperatures above ${T}_{c}=143$ \ifmmode^\circ\else\textdegree\fi{}K this interaction is manifest as an antiresonance interference shape in the Raman spectrum, similar to that in AlP${\mathrm{O}}_{4}$; however, the interacting modes in Cs${\mathrm{H}}_{2}$AS${\mathrm{O}}_{4}$ are heavily damped, in contrast to AlP${\mathrm{O}}_{4}$. The observed spectra are in good agreement with a spectral distribution function obtained from a Green's-function calculation. Very similar results are obtained for K${\mathrm{H}}_{2}$As${\mathrm{O}}_{4}$.

Symmetrical hydrogen bonds in the crystal structure of calcium bis(dihydrogen arsenate): a neutron-diffraction study

Neutron-diffraction analysis (final R-value 0·025 over 930 independent reflexions) of the crystal structure of calcium bis(dihydrogen arsenate), Ca(H2AsO4)2, strongly indicates that inter-ion oxygen–oxygen separations of 2·436(3) and 2·444(3)Å contain symmetrical hydrogen bonds.

Some physical properties of single crystals of normal and deuterated rubidium dihydrogen arsenate. I. Piezoelectric and elastic properties: Adhar, R.S., British Journal of Applied Physics, Series 2, Vol 2, No 2 (February 1969) pp 171–175 (1468)

Some physical properties of single crystals of normal and deuterated rubidium dihydrogen arsenate. I. Piezoelectric and elastic properties: Adhar, R.S., British Journal of Applied Physics, Series 2, Vol 2, No 2 (February 1969) pp 171–175 (1468)

Some physical properties of single crystals of normal and deuterated rubidium dihydrogen arsenate I. Piezoelectric and elastic properties

The elastic and piezoelectric constants of single crystals of rubidium dihydrogen arsenate grown in H2O, and of rubidium dideuterium arsenate grown in D2O, have been measured in the temperature range 20-80°C. The shear elastic constants S44 and S66 and the extensional elastic constants S11 and S33 increase slightly on deuteration while their temperature coefficients decrease slightly. The piezoelectric constants d14 and d36 increase by 48% and 61% respectively on deuteration at 25°C. For normal RbDA the elastic constants measured at 25°C are: S11 = 22·8 × 10−12 m2 N−1, S12 = 8·5 × 10−12 m2 N−1 S13 = −1·8 × 10−12 m2 N−1, S33 = 25·4 × 10−12 m2 N−1 S44 = 96·0 × 10−12 m2 N−1, S66 = 232·0 × 10−12 m2 N−1. The piezoelectric constants are d14 = 9·9 × 10−12 C N−1 and d36 = 28·5 × 10−12 C N−1.

Some physical properties of single crystals of normal and deuterated rubidium dihydrogen arsenate II. Electro-optic and dielectric properties

The electro-optic and dielectric constants of single crystals of rubidium dihydrogen arsenate grown in H2O, and of rubidium dideuterium arsenate grown in D2O, have been measured. On deuteration the relative dielectric constant K33 is increased from 28·5 to 42·5 and K11 is increased from 54·5 to 71·5 at 25°C. The half-wave retardation voltage Vλ/2, measured at 500 nm is decreased from 3·8 kv to 3 kv and the electro-optic constant r63 is increased from 16·7×10−10 cm v−1 to 21·6×10−10 cm v−1 on deuteration. The loss tangent tan δ33, measured at 1 kHz and at 25°C, is about 2·6 for D-RbDA and 5·2 for RbDA. The specific resistivity ρ33 for RbDA is 3·4×106 Ω cm and that for D-RbDA is 3·6×107 Ω cm, measured at 25°C. The input power requirement using these crystals in an electro-optic modulator is compared to that of KDP.

Catalysed hydrolysis of an acyl-activated anilide in buffered solutions

The hydrolysis of N-(4-nitrophenyl) dichloroacetamide is catalysed by buffer reagents acting as general acids and bases. The dihydrogen phosphate, dihydrogen arsenate, and hydrogen carbonate ions are abnormally effective as general-acid catalysts, and the carbonate ion is probably abnormally effective as a general base. The results of this study do not lend support to the concept of bifunctional catalysis, and are discussed in terms of hypothetical energy–reaction-co-ordinate profiles for proton transfer.

Crystal structure of 1-methyl-2-quinolonium dihydrogen arsenate

This compound crystallises with four 4QH3AsO4(Q = 1-methyl-2-quinolone) molecules in a cell of space group Pna21, with a= 18·928, b= 12·717 and c= 4·875 Å. The structure has been solved and refined to R= 12% for 1281 independent X-ray reflexions. The H2AsO4– groups are linked into infinite helical chains by hydrogen bonds. The quinolonium residues (QH+) are attached, laterally, to the helix by hydrogen bonds from the protonated carbonyl group, with O–H ⋯ O = 2·495 Å. In discrete XO4-ions, the sum of the four X–O bond-lengths is approximately constant. The sum of the As–O distances in this crystal is 6·74 Å, which is within the range 6·6–6·8 Å found in other arsenates.

Some Physical Properties of Single Crystals of Normal and Deuterated Cesium Dihydrogen Arsenate

The elastic, dielectric, and piezoelectric constants of single crystals of cesium dihydrogen arsenate grown in H2O and of cesium dideuterium arsenate grown in D2O have been measured in the temperature range of 20°–80°C. The shear elastic constants S44 and S66 increase, while the extensional elastic constants S11 and S33 decrease on deuteration. Considerable changes in the temperature coefficients of three constants S11, S33, and S66 are produced by deuteration. Zero temperature coefficients of frequency of extensional and shear resonator plates are obtained in the Z plane, which are useful in electromechanical applications.