Arsenic Spectrum

History—Preparation—Allotropy—Colloidal Arsenio—General Physical Properties of Arsenic—Spectrum—Chemical Properties—Atomic Weight—... 

Tris(dimethylamino)arsine (d2o 1.1248 nd 1.4848)3 is a colorless liquid which is readily hydrolyzed to form arsenic (III) oxide and dimethylamine when brought into contact with water. The compound is soluble in ethers and hydrocarbons. The product is at least 99.5% pure (with respect to hydrogen-containing impurities) as evidenced by the single sharp peak at —2.533 p.p.m. (relative to tetramethylsilane) seen in the proton nuclear magnetic resonance spectrum of the neat liquid. 

Radiation is derived from a sealed quartz tube containing a few milligrams of an element or a volatile compound and neon or argon at low pressure. The discharge is produced by a microwave source via a waveguide cavity or using RF induction. The emission spectrum of the element concerned contains only the most prominent resonance lines and with intensities up to one hundred times those derived from a hollow-cathode lamp. However, the reliability of such sources has been questioned and the only ones which are currently considered successful are those for arsenic, antimony, bismuth, selenium and tellurium using RF excitation. Fortunately, these are the elements for which hollow-cathode lamps are the least successful. 

Pho hate and arsenate, not surprisingly, are competitive inhibitors of the enzymes with Ki s of 1-10 mM (85,87). Binding of phosphate to reduced uterofenin results in a red shift of the Xmax and loss of most of the intensity of the characteristic EPR spectrum (84,87). Upon standing in air, the oxidized uterofeirin-phosphate complex is formed, in which the phosphate is tightly bound (87,88,89). 

It is well known that vanadium can replace phosphorus or arsenic in the apatite lattice. Most of the orthovanadates which crystallize in this form have been investigated by IR and Raman spectroscopic techniques 62—64). The results of these studies are summarized in Table 4. The space group of all of these compounds is certainly C ft with the VO4 ion lying on a C site. Therefore, one should always find a nine band spectrum. Phosphorus apatites behave similarly, as seen in Ref. (65). 

Munch, J.C. Ottow, J.C.G. (1982) Einflufi von Zellkontakt und Eisen(III)-Oxidform auf die bakterielle Eisenreduktion. Z. Pflanzener-nahr. Bodenk. 145 66-77 Munoz, J.A., Gonzalo, A. Valiente, M. (2002) Arsenic adsorption by Fe(III)-loaded open-celled sponge. Thermodynamic and selectivity aspects. Envir. Sci. Techn. 36 3405-3411. Murad, E. Bishop, J.L. (2000) The infrared spectrum of synthetic akaganeite, P-EeOOH. Am. Min. 85 716-721... 

The phosphorus chemical shift observed for the arsenic derivative 5 P = 315 is in accordance with the monomeric structure (39). This, however, is not the case for that observed for the antimony derivative, P = 44.5. The mass spectrum of the latter confirms its dimeric structure (37). 

Another area of concern that has not received adequate attention is the possible contamination of the sulfur products. Feedstocks to these refineries will contain a full spectrum of the elements of the periodic table. Theoretical analysis indicates that certain of these materials may undergo chemical reactions and end up in the sulfur plant feed. Theoretically, we can expect a significant contaimination by arsenic, selenium, tellurium, and perhaps mercury. ... 

FIG. 1. NMR spectrum (1H, 500 MHz) of a synthetic mixture of six marine arsenic compounds in seawater. Each compound was present at a concentration of 10 fig As/mL. (Spectrum courtesy of Dr. L. Byrne.)... 

Although several chemicals, e.g. arsenicals and organophosphorus compounds, had been used with some effect to treat specific helminth infections, the introduction in 1930 of phenothiazine (1) was a revolutionary event in the control of gastrointestinal worms. Although its spectrum of activity was narrow compared to modern anthelmintics and its dose level was rather high (600-800 mg kg-1), it was the veterinary anthelmintic of choice until the 1960s. 

Spectrum.—The line emission spectrum of arsenic has been the subject of much investigation3 throughout the whole range of radiations accessible to photography and under varying conditions of excitation. It is characterised by a great number of lines and is difficult to analyse because many important lines lie in the far ultraviolet or in the infra-red. 

Most of the lines in the are spectrum are easily reversed. In order to differentiate the arc and spark spectra Buffam and Ireton 5 used an under-water oscillatory condenser discharge with a suitable condenser capacity in the circuit the spectra were produced between poles of metallic arsenic in a vessel through which water circulated continuously, and were photographed by means of Hilger spectrographs. The arc lines were inverted on a dark continuous background, while the spark lines were not. 

The emission spectrum of arsenic vapour shows a group of bands, attributable to As2 molecules, in the region 2700 to 4200 A., whilst several bands in the region 2148 to 3047 A. appear to be due to As atoms.9 The extinction coefficient of arsenic vapour at various temperatures and over the range 3000 to 3900 A., has been measured.10... 

A fluorescence spectrum of arsenic vapour, after exposure to a mercury lamp at a high temperature has been observed (see p. 39).2... 

The X-ray and series spectra,7 and also the /3-ray spectrum of radioactive arsenic,8 have been examined. 

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