Calcium Tartrate Research Articles

Noncentrosymmetry observed in cac4h4o64h2o crystals by nonlinear optical measurements

Abstract Calcium tatrate tetrahydrate (L-CTT) is reported to have point group symmetry mm at room temperature. Second harmonic generation experiments indicate that calcium tartrate tetrahydrate prepared from pure L-tartaric acid has the noncentrosymmetric point group mm2. All the nonlinear optical d-coefficients are determined. Linear optical properties of this material such as: refractive indices and absorption constant are measured in the range 200 nm Λ <2000 nm and the phase matching conditions for optical frequency doubling are derived. Non critical type I phase matching can be achieved in L-CTT at room temperature for a fundamental wavelength of Λ = 816 nm.

Calcium tartrate gel

A method for preparation of a gel for chromatography has been developed. The adsorbent is calcium tartrate treated with potassium phosphate. By changing the temperature of synthesis (10–65°C) and concentration of the salts (calcium chloride and sodium potassium tartrate) from 0.3 to 3.0 m, we have been able to prepare adsorbent crystals of definite sizes in the range 35–200 μm. In all cases, for synthesis of adsorbent, the Ca 2+/K +Na + ratio was greater than 1. After treatment of calcium tartrate crystals with 0.075–1.5 m potassium phosphate at 80–100°C and pH 8.5–9.0, an appropriate chromatographic adsorbent was prepared. The chromatographic properties of calcium tartrate gel have been studied. The adsorbent permits flow rates of 25–150 ml/h, depending on the particle size. The capacity of calcium tartrate gel for binding BSA, RNA, and DNA was similar to that of Tiselius' hydroxyapatite (A. Tiselius, S. Hjerten,O¨. Levin (1956) Arch. Biochem. Biophys. 65, 132–155). The spheric shape of gel particles permits uniform and compact packing of adsorbent under the conditions of column chromatography.

Calculation of the effective second-order non-linear coefficients along the phase matching directions in acentric orthorhombic biaxial crystals

The effective second-order non-linear coefficients for the four acentric orthorhombic biaxial point groups are formulated in a general way from the definition given by Boyd and Kleinman as a function of the crystal symmetry and direction of propagation of light in the crystal. The effective non-linear coefficients are calculated numerically in the case of the second harmonic generation at 1064 nm from a Nd:YAG laser, under the phase matched condition for eight orthorhombic nonlinear crystals: ammonium oxalate, iodic acid, lithium formate, potassium titanyl phosphate, calcium tartrate tetrahydrate, lithium gallium oxide, barium sodium niobate and potassium niobate.

Fourier transform infrared spectroscopic study of the role of tartaric acid in glass-ionomer dental cements.

(+)-Tartaric acid is incorporated into glass-ionomer dental cements to control the setting characteristics. FTIR has been used to examine the cements as they set, and has confirmed previous results that (+)-tartaric acid reacts more readily with the glass than does poly(acrylic acid), thereby delaying the setting of the cement. Subsequently, ions released by the glass become available for reaction with the polyacid, and gelation occurs. (+)-Tartaric acid not only reacts rapidly to yield calcium tartrate, but also enhances the rate at which aluminum polyacrylate is formed within the cement. Mesotartaric acid, by contrast, while rapidly forming calcium tartrate, does not enhance the rate of aluminum polyacrylate formation. As a result, this latter isomer merely suppresses the setting process; unlike (+)-tartaric acid, it does not also sharpen the set.

Luminescence spectroscopy of Eu 3+ in calcium tartrate tetrahydrate

Single crystals of calcium tartrate tetrahydrate doped in Eu 3+ are readily grown by a gel technique. Luminescence spectroscopy shows that the Eu 3+ occupy a set of energetically similar sites, with the majority of them having D 2 symmetry. This symmetry is due to a small distortions of the original substitutional site caused by the necessity of a charge compensation. The decay curves of the luminescence from the 5D 0 level in agreement with the spectral results and show that the various sites differ in the number of neighbouring OH groups. In contrast to site-selection spectroscopy results on the same material doped with UO 2 2+, we find no evidence of a pseudo-continuous range of ‘glassy’ sites.

Factors Affecting Induced Calcium Tartrate Precipitation from Wine

The rate of calcium tartrate precipitation was measured in wine after addition of calcium carbonate. Wine pH has little, if any, effect on the rate of precipitation, only on the final equilibrium concentration. Low temperatures slow the rate of precipitation but result in greater calcium tartrate stability. Addition of calcium tartrate seed crystals increases the rate of precipitation. Malic acid inhibits calcium tartrate precipitation during the period when nucleation controls crystal growth. Measurement of tartaric acid and calcium during precipitation shows the stoichiometry to be 1:1 during all phases of crystallization.

Site selection spectroscopy of UO 2+2 in calcium tartrate tetrahydrate crystals

Single crystals of calcium tartrate tetrahydrate containing several per cent of the uranyl ion are readily grown. These crystals are strongly luminescent at room and lower temperatures. Selective excitation shows the presence of a large number of both discrete and disordered sites. In contrast to the behaviour of the uranyl ion in oxide glasses, the concentration of sites with an in-plane coordination number of six is small and the vast majority of sites have a coordination number of five.

Noncentrosymmetry Observed in CaC4H4O6 · 4H2O Crystals by Nonlinear Optical Measurements

AbstractCalcium tartrate tetrahydrate (L‐CTT) is reported to have point group symmetry mmm at room temperature. Second harmonic generation experiments indicate that calcium tartrate tetrahydrate prepared from pure L‐tartaric acid has the noncentrosymmetric point group mm2. All the nonlinear optical d‐coefficients are determined. Linear optical properties of this material such as: refractive indices and absorption constant are measured in the range 200 nm &lt; λ &lt; 2000 nm and the phase matching conditions for optical frequency doubling are derived. Non critical type I phase matching can be achieved in L‐CTT at room temperature for a fundamental wavelength of λ = 816 nm.

Crystal growth in syndiotactic poly(vinyl alcohol) hydrogels

Aqueous solutions of syndiotacticity-rich poly(vinyl alcohol) (s-PVA) form gels easily. The optimum condition of growth of the calcium tartrate crystal formed by diffusing calcium chloride into hydrogels containing tartaric acid was studied with use ofs- PVA of a syndiotacticity of 56 % and a degree of polymerization of 1460. The crystal grew in the gel of the concentrations of 2 % s-PVA and of 0.5 N tartaric acid at pH=4. The relation between the formation of Liesegang rings and shear modulus of a gel was studied by diffusing silver nitrate into gels containing potassium chromate. The distance between rings decreased with increasing shear modulus of a gel in the range from 670 to 7500 dyne/cm2. The Liesegang rings were not formed for the shear modulus gel for 280 and 16200 dyne/cm2.

Ferroelectricity in calcium tartrate single crystals

Abstract The paper reports ferroelectricity in calcium tartrate single crystals. This fact is established through a study of dielectric properties and hysteresis loops.

Potassium Localization in the Grape Berry Pericarp by Energy-Dispersive X-Ray Microanalysis

The distribution of the major solutes, particularly potassium, in the berry pericarp of the grape variety Tarrango was investigated. The osmotic potentials (ψ_π) of the skin and pulp were the same, viz. -5.6 MPa. Glucose and fructose accounted for 84% of the pulp ψ_π, although the contribution of these sugars to skin ψ_π was significantly less, viz. 58%. The tartrate to malate ratios were 0.4 and 2.4 in the skin and pulp, respectively. The mean concentration of K in the skin was <i>ca</i> 300 m<i>M</i> which was four to five times higher than the concentration in the pulp. Although crystals of a calcium salt (tartrate?) were seen in cryo-scanning electron micrographs of hypodermal cells, crystalline K salts were never observed. The calculated contribution of skin K and complementary anion to skin ψ_π was <i>ca</i> 20%. X-ray microprobe mapping of Tarrango hypodermal cells showed that K was not uniformly distributed across the skin. Similar observations were made for Shiraz berries. This inhomogeneity of K accumulation results in some cells with vacuolar concentrations between 0.5 and 1.0 <i>M</i>. It is proposed that malate is the predominant complementary anion to K in high-K hypodermal cells, and the likely salt to acid balance in the vacuole of these cells results in pH levels significantly greater than the pH level of the pulp, viz. 5 or higher. While K occurs largely as a soluble salt, the high Ca content of the skin (48 m<i>M</i>) probably leads to the precipitation of the greater part of the tartrate as crystalline bundles of calcium tartrate. The preferential sequestering of K in the skin is indicative of a very rudimentary homoeostatic process which assists in regulating K levels in the pulp.

Effect of X-ray orγ-ray irradiation on the dielectric properties of calcium tartrate single crystals

Effect of X-ray orγ-ray irradiation on the dielectric properties of calcium tartrate single crystals

Raman spectroscopy and dielectric constants of ferroelectric Rochelle salt and calcium tartrate

The Raman spectrum of Rochelle salt (NaKC4H4O4d6.4H2O) has been measured in greater detail than hitherto, while the Raman spectrum of calcium tartrate (CaC4H4O6.4H4O) has been recorded for the first time; mode assignments for both materials have been made where possible. The spectrum of Rochelle salt shows no important changes on passing through either of the ferroelectric phase transitions,a nd dielectric constant measurements on this material confirm departures from Curie-Weiss behaviour. Dielectric constant measurements on calcium tartrate show no evidence of any phase transition between 250 and 495K.

Structure of calcium tartrate tetrahydrate

Structure of calcium tartrate tetrahydrate

Complex-forming equilibria in isotachophoresis : I. Computer simulation of the calcium tartrate system in the steady state

A theory for kinetically labile complex equilibria in isotachophoresis has been described for the purposes of computer simulation. Simulated ratios of potential gradients, R E = E t/ E L, have been obtained for Ca 2+ and tartrate ions coexisting with calcium tartrate complexes. The simulated values agreed well with the observed ones and the validity of the simulation has been confirmed. The simulation can be used for the determination of optimal conditions and also for the estimation of stability constants and/or mobilities of complexes.

Optical absorption spectrum of Cu 2+ in calcium tartrate tetrahydrate

Copper doped single crystals of calcium tartrate tetrahydrate are grown from silica gel. The optical absorption spectrum is investigated with polarised and unpolarised beams of incident light. The spectrum is attributed to the Cu 2+ ion in C 4V symmetry associated with spin-orbit coupling. The following crystal field parameters are evaluated: Dq = 1000 cm −1; λ = −830 cm −1; Ds = 1540 cm −1; Dt = 470 cm −1.

Absorption spectrum of Cr 3+ in calcium tartrate tetrahydrate

Calcium tartrate tetrahydrate single crystals doped with Cr 3+ ions are grown from silica gel. The optical absorption spectrum is studied at the laboratory and liquid nitrogen temperatures. From the analysis of the unpolarised and polarised spectra, the site symmetry of the Cr 3+ ion is attributed to octahedral with a small tetragonal distortion. The following crystal field parameters are evaluated. B = 655 cm -1 C = 2948 cm -1 Dq = 1800 cm -1 Dt = 40 cm -1

Spectroscopic studies of Ni2+ in calcium tartrate tetrahydrate

The optical absorption spectrum of a single crystal of calcium tartrate tetrahydrate, doped with Ni2+ ions, is investigated at laboratory and liquid nitrogen temperatures. From the analysis of the unpolarised and polarised spectra, the site symmetry of the Ni2+ ion is attributed to an elongated octahedron with a small tetragonal (C4v) distortion. The analysis results in the following crystal field parametersB=875 cm−1,C=3980 cm−1,Dq=900 cm−1, Dt=32cm−1.

Deacidification of Musts from the Western United States by the Calcium Double-Salt Precipitation Process

Musts of high acidity were deacidified by the calcium double-salt (calcium malate-tartrate) precipitation process, with the use of Acidex. Ten lots of white and red musts (eight of <i>Vitis vinifera</i> and two of <i>V. labrusca</i>) were used. Must acidities ranged from 0.96 to 1.68 g/100 ml. By precipitation of the calcium double salt, the acidities were reduced to 0.8 g/100 ml for white musts, and 0.7 g/100 ml for red musts. Although precipitation was not the theoretical exact equimolar amounts of malic acid and tartaric acid, quantitative efficiency of the method of deacidifcation was judged to be good. The problem of calcium tartrate instability was judged to be minimal after storage of the wines for six months.

Deacidification of Musts from the Western United States by the Calcium Double-Salt Precipitation Process

Musts of high acidity were deacidified by the calcium double-salt (calcium malate-tartrate) precipitation process, with the use of Acidex. Ten lots of white and red musts (eight of <i>Vitis vinifera</i> and two of <i>V. labrusca</i>) were used. Must acidities ranged from 0.96 to 1.68 g/100 ml. By precipitation of the calcium double salt, the acidities were reduced to 0.8 g/100 ml for white musts, and 0.7 g/100 ml for red musts. Although precipitation was not the theoretical exact equimolar amounts of malic acid and tartaric acid, quantitative efficiency of the method of deacidifcation was judged to be good. The problem of calcium tartrate instability was judged to be minimal after storage of the wines for six months.