Potassium atomic spectrum

Fig. 13.10 Sonoluminescence spectrum of potassium-atom emission from helium-saturated KC1 aqueous solution at 148 kHz. The spectrum shows slightly asymmetric broadening toward blue side, which is in contrast with the potassium line in argon-saturated solution...

Potassium chlorate, potassium perchlorate etc, which contain potassium atoms create undesirable spectra continuous spectrum caused by the atoms and atomic line spectra. The former appears in almost all the visible zone... 

Potassium chlorate, potassium perchlorate etc, which contain potassium atoms create undesirable spectra continuous spectrum caused by the atoms and atomic line spectra. The former appears in almost all the visible zone and is the most intensive at about 4500A(blue). This spectrum makes the flame white, and sometimes it is used to produce a white flame. This spectrum cannot be rejected unless the potassium salts are precluded from the composition. If good colouring is desired, ammonium perchlorate must be used in place of above oxidizers. In the latter, the atomic line spectra are very weak and do not much disturb the colour. 

Tests by precipitation are difficult because the salts of these cations exhibit near-universal solubility. Both Na and K ions are most easily detected with a flame test. When a solution containing sodium ions is brought into contact with a flame, the characteristic orange-yellow color of the emission spectrum of sodium atoms is observed. For potassium atoms, a pale violet color results. To detect the presence of NH4, we use the fact that the ammonium ion is the conjugate acid of the weak volatile base ammonia. Heating some of the original solution (not the final solution, which contains NH4 ions added in the fractional precipitation scheme) with excess strong base will liberate ammonia. 

On the other hand, the P H NMR spectrum of 37 consists of a set of three signals corresponding to an AA BB XX spin system (Table 4.1), which indicates that the dianionic P4 chain with the expected dW-trans conformation is retained in solution, as was observed in its molecular structure determined by X-ray diffraction. In the solid state, the nickel atom and the four phosphorus atoms of the chain form a puckered five-membered ring (Table 4.2). Interestingly, the nickel atom has pseudo-octahedral coordination, with the diphosphene ligand (P5 and P6) and the terminal phosphorus atoms of the (P4Ph4) ligand (PI and P4) in the equatorial positions, and the potassium atoms (K1 and K2) in the axial positions with short K--Ni distances of 318.5(2) pm for K1 and 310.7(2) pm for K2, which are the shortest distances reported for an Ni -K interaction in a complex (Fig. 4.18). 

In contrast, Skell and co-workers 169) demonstrated that there could be prepared, by the metal atom method, a reasonably well-defined, paramagnetic, yellow TijCCgHgls compound which, in THF, is rapidly reduced with potassium to yield a fairly stable, green solution of the diamagnetic dianion. The H-NMR spectrum and the analytical data were all consistent with the formulation of the green dianion shown, which appears to be the... 

Proton nmr titration experiments of [26] and [27] with KPF6 in acetonitrile revealed that in solution both compounds form 1 1 intramolecular sandwich complexes with the potassium cation. A number of alkyl-, vinyl- and azo-linked bis(benzo-15-crown-5) ligands are well known to exhibit this mode of K+ coordination. In the case of [26], a solid-state potassium complex was isolated whose elemental analysis and fast-atom bombardment mass spectrum ([26] K+ = 1083 complex ion) was in agreement with 1 1 complex stoichiometry (Fig. 20). 

The potassium salt of the 2,2 -dipyridyl acetylene anion-radical represents another important example. In this case, the spin and charge are localized in the framework of N-C-C=C-C-N fragment. The atomic charge on each nitrogen atom is -0.447, that is, close to unity in total. The energy of this ion pair is minimal when the potassium counterion is located midway between the two rather close nitrogen lone pairs. Such a structure is consistent with the fact that the ESR spectrum of this species is almost insensitive to temperature. It means that the counterion does not hop between two remote sites of the anion-radical (Choua et al. 1999). 

The formation of a radical-anion with a very short lifetime on the surface of a sodium-potassium alloy during the reduction of thieno[3,2- ]-thiophene (2) at —100° was established by ESR (theoretical and experimental spectra are presented). The formation of the thieno[2,3-61-thiophene (1) radical-anion even under such extreme conditions was not observed. The difference in the stability of radical-anions of thienothiophenes 1 and 2 was accounted for by a greater degree of conjugation in thienothiophene 2 molecule as compared to 1. The spectrum of the thienothiophene 2 radical-anion distinctly exhibits two types of hydrogen atoms with coupling constants 4.87 and 0.52 Gauss. The... 

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