Tellurium, spectrum

Figure ( shows the 1S-2S two-photon spectrum with its two hyperfine components, recorded in this way. Shown below is a Doppler-free saturation spectrum of Tej, observed simultaneously with the cw dye laser at the fundamental wavelength. The tellurium spectrum appears shifted by 60 MHz towards lower frequencies, since a 120 MHz acousto-optic Bragg cell is employed as a chopper. The component i is thus found in nearly perfect coincidence with the hydrogen F 1- 1 resonance. The absolute frequency of the nearby Te2 component bj has recently been measured interferometrically to within 1) parts in 10 . Using this line as a reference and taking advantage of the auxiliary Te line ii, the frequency of the centroid of the two hyperfine components was measured to be f(1S-2S)... 

The intriguing radical cation [Te N(SiMe3)2 2] " is formed (as the blue AsFg salt) by oxidation of Te[N(SiMc3)2]2 with AsFs. This deep blue salt is monomeric in the solid state with d(Te-N) = 1.97 A, consistent with multiple bonding. The broad singlet in the EPR spectrum indicates that the unpaired electron is located primarily on the tellurium... 

The latter do not yield l,3-dichalcogen-2,4-phosphasilacyclobutanes if they are treated with excess elemental sulfur and tellurium. Compound 23a has been characterized by its 31P-NMR spectrum, which shows a singlet signal at 8 = -126.0, and by l25Te satellites with /(P,Te) = 222 Hz. The composition of 23b,c was proved by mass spectrometry and their... 

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. 

Figure 4. Electric quadrupole spectrum of Te in pure Te at 4.8°K. Source, in Cu at 82°K. Total absorber thickness, 30.0 mg./sq. cm. of tellurium enriched in Te—i.e., Te/Te = 40.4%. Individual lines (A this doublet have a full width at half maximum of 0./3 cm./sec. Our experimental line widths for absorbers vary from 0.67-101 cm./sec.

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. ... 

Spectrum.5—The arc and spark spectra of tellurium have been investigated, the arc being produced in an atmosphere of carbon dioxide between tellurium electrodes or between carbon electrodes one of which carried pieces of tellurium in a small cavity. Fifteen distinctive lines between 3175 and 2081 A 6 and forty of wave-length less than 2080 A 7 have been measured. The most prominent lines are 2142-75, 2259-02, 2383-24, 2385-76, 2769-65 and 3175-13 A. The lines at 2769-65 and 3175-13 have been shown to be distinct from those of antimony (2769-94) and tin (3175-04) by photographing the spectra of mixtures of these elements with tellurium, when in each case the two separate lines were obtained.8... 

When illuminated by an incandescent gas lamp, tellurium vapour exhibits an intense bluish-green fluorescence. Under the light of a mercury vapour lamp the fluorescence is much less intense. The fluorescence spectrum consists of regularly spaced bands in the visible region.12... 

Tellurium tetrachloride is a colourless, crystalline solid it melts at 225° C.1 to a yellow liquid, the colour of which deepens as the boiling-point, 390° C., is approached. The vapour is yellow and at 440° C. has a density agreeing closely with the formula TeCl4, although above 500° C. appreciable dissociation occurs, probably into the dichloride and chlorine. Unlike tellurium dichloride, the vapour of which shows marked absorption bands, the vapour of the tetrachloride gives no definite absorption spectrum.2... 

The ions (w) resulting from loss of cyclopropane from the molecular ions were only observed for the sulfur, selenium and tellurium analogues. The alternative mode of fragmentation in which the hydrocarbon fragment (y) carries the charge provides the base peak for the tetrahydrofuran spectrum, but is only a minor feature of the spectra of the selenium and tellurium analogues. The hydrocarbon ion C4H/ (z) is a minor feature of the tetrahydrothiophene spectrum but provides the base peak of the spectra of the selenium and tellurium analogues. 

Loss of tellurium is responsible for the base peak m/e 54 in the mass spectrum of 2,5-dihydrotellurophene and there is also evidence for some dehydrogenation to telluro-phene (81JA2715). 

Thus far no reports have appeared on the isolation of 1,3-ditellurolylium cation salts in a pure state. Attempts to prepare 1,3-ditellurolylium boron tetrafluoride and its derivatives via treatment of 1,3-ditelluroles with tri-phenylmethyl boron tetrafluoride in MeCN solution failed (82TL1531). However, formation of the 1,3-ditellurolylium cation 74 was revealed by the H NMR spectrum in which the 2-H proton was shown to give a very low-field triplet (8 15.0 ppm, 4/Hh = 1.2 Hz). Cation 74 is sufficiently stable in solution only at low temperature. When an acetonitrile solution of 74 obtained from 1,3-ditellurole was heated to 30°C, the initial H NMR spectrum drastically changed to the A2X spectral pattern (8 13.8 ppm, d and 10.3 ppm, /, iJ = 6.9 Hz) corresponding to the spectrum expected for the 1,2-ditellurolylium cation 75. A plausible reaction scheme is shown below. A further elevation of the temperature of the solution resulted in an unidentified destruction process accompanied by the extrusion of elemental tellurium. 

Such a structure is supported by the 19F-NMR spectrum (205) and has been confirmed more recently by electron diffraction for Se,0,FK and for the tellurium analog (207). 

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