Strontium emission

WEB Strontium-90 is a dangerous byproduct of atomic testing because it mimics the action of calcium in the body. It decays in two beta emissions to give zirconium-90 (Nudear mass = 89.8824 g). 

Starch as sample diluent, 173 Steel strip, x-ray gaging, 69-71 Strontium, determination by x-ray emission spectrography, 329 in solution, discussion of background in x-ray emission spectrography, 213, 214... 

C07-0112. The bright red color of highway safety flares comes from strontium ions in salts such as Sr(N03)2 and SrC03. Burning a flare produces strontium ions in excited states, which emit red photons at 606 nm and at several wavelengths between 636 and 688 nm. Calculate the frequency and energy (kJ/mol) of emissions at 606, 636, and 688 nm. 

In general, excited atoms emit spectral lines, i.e. the radiation lies in very narrow wavelength ranges of width 10 to 10 nm. In practice, atomic resonance lines from species, such as strontium in a red star, contribute little to the visual effect since the emission falls in the short wavelength part of the spectrum (this line may be observed in a Bunsen burner flame at 461 nm). 

During combustion, strontium nitrate and strontium carbonate decompose to give strontium oxide whose spectrum is seen as a pinkish flame due to the positions of the emission bands and to the difficulty in obtaining a high concentration of strontium oxide vapour in the flame. This difficulty is due to the high sublimation temperature of the oxide which is in excess of 2500 °C. 

An excess of chlorine, introduced into reaction (8.7) causes a shift to the left and an improvement in the flame saturation of strontium monochloride. Table 8.3 shows the main emission bands/lines for a red star. Figure 8.8 shows the radiant spectrum of a typical red star. 

FIG. 7.1 Emission spectrum of a red flare. Emission is concentrated in the 600-700 nm region. The primary emitting species are SrCI and SrOH molecules in the vapor state. The composition of the flare was potassium perchlorate (20.5%), strontium nitrate (34.7%), magnesium (24.4%), polyvinylchloride (11.4%), and asphaltum (9.0%). Source H. A. Webster III, "Visible Spectra of Standard Navy Colored Flares," Proceedings, Explosives and Pyrotechnics Applications Section, American Defense Preparedness Association, Fort Worth, Texas, September, 1983. 

The best flame emission in the red region of the visible spectrum is produced by molecular strontium monochloride, SrCl. This species - unstable at room temperature - is generated in the pyrotechnic flame by a reaction between strontium and chlorine atoms. Strontium dichloride, SrCl 2, would appear to be a logical precursor to SrCl, and it is readily available commercially, but it is much too hygroscopic to use in pyrotechnic mixtures. 

The SrCl molecule emits a series of bands in the 620-640 manometer region - the "deep red" portion of the visible spectrum. Other peaks are observed. Strontium monohydroxide, SrOH, is another substantial emitter in the red and orange-red regions [1,11]. The emission spectmm of a red flare is shown in Figure 7.1. 

Ionisation is an equilibrium and may be shifted to the left by addition of another readily ionised element to the sample which produces electrons. The emission lines from the added metal are unlikely to interfere because AE lines are very narrow, and thus there will be no overlap, e.g. strontium chloride solution is added in order to suppress the ionisation of K in the BP assay of effervescent KCI tablets. 

The above considerations led us to initiate work with Sr-85 as a tracer for cryptand [2.2.2]. Strontium-85 decays with emission of a 514 keV gamma, is commercially available and has a convenient... 

When preparing the cesium- and barium-saturated clays, the 1.0 M solutions used were decanted (after centrifuging) and analyzed semiquantitatively by emission spectroscopy. From those analyses, it appears that the following species were desorbed sodium, potassium, calcium, magnesium, and strontium. It further appeared that desorption of potassium was almost unique to cesium sorption whereas, desorption of the other species appeared to be common to both cesium and barium sorption. Small amounts of other elements such as nickel and copper were also detected by the analyses. However, to what extent the observed concentrations may represent desorption and to what extent they may represent the dissolution of sparingly soluble substances (particularly hydroxide species) is as yet-uncertain. The apparent concentrations of the desorbed species per gram of clay are given in Table III. 

CaS Ce3+ is a green-emitting phosphor. On activation with 10-4 mol% cerium, the emission maximum occurs at 540 nm. Greater activator concentrations lead to a red shift substitution of calcium by strontium, on the other hand, leads to a blue shift SrS Ce3+ (10 4 mol% cerium) has 2max = 483 nm [5.344]. 

Calcium or strontium sulfides, doubly activated with europium-samarium or cerium-samarium, can be stimulated by IR radiation since Sm3+ acts as a trap through the transition Sm3+ + e -> Sm2+ [5.341], Emission occurs at europium or cerium and leads to orange-red (SrS Eu2 +, Sm3+) or green (CaS Ce3 +, Sm3+) luminescence. 

Finally, we note that the photocorrosion process is strongly pH-dependent, occurring most readily in strongly acid solutions, and that the presence of a carboxylic acid is required for the occurrence of severe photocorrosion. In Table II we present analytical results, based on inductively coupled argon plasma (ICP) emission spectroscopy, for representative electrolyte solutions after 6-8 hr. of photo-Kolbe electrolysis with n-SrTiC anodes. It can be seen that the formation of soluble strontium and titanium species is... 

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