Bunsen-Kirchoff

L. rubidus, deepest red) Discovered in 1861 by Bunsen and Kirchoff in the mineral lepidolite by use of the spectroscope. 

Rubidium was discovered ia 1861 by Bunsen and Kirchoff by means of an optical spectroscope. It was named for the prominent red lines ia its spectmm, from the Latin word rubidus meaning darkest red. Bunsen prepared free mbidium duriag the same year by an electrolytic method. After cesium, mbidium is the second most electropositive and alkaline element. The two isotopes of natural mbidium are Rb [13982-12-1] (72.15%) and Rb [13982-13-3] (27.85%). The latter is a beta-emitter having a half-life of 4.9 x 10 ° yr. Twenty-four isotopes of mbidium are known. 

Cesium, first discovered by Bunsen and Kirchoff ia 1860 while examining spring water, was the first element discovered spectroscopically (1). The name, comes from the Latin caesius, sky blue, and refers to the characteristic blue spectral lines of the element. Cesium salts were not successfully reduced to metal until 1881. Electrolysis of the molten chloride did not yield cesium metal under the same conditions that led to the reduction of the other alkaU metal chlorides. 

Chemistry and the Spectrum before Bunsen and Kirchoff. (With Tillmon H. Pearson). J. Chem. Educ., 28, 267-71 (1951). 

Rubidium - the atomic number is 37 and the chemical symbol is Rb. The name derives from the Latin rubidus for deepest red because of the two deep red lines in its spectra. It was discovered in the mineral lepidolite by the German chemist Robert Wilhelm Bunsen and the German physicist Gustav-Robert Kirchoff in 1861. Bimsen isolated rubidium in 1863. 

Cesium was discovered by Bunsen and Kirchoff in 1860. It is found in the minerals pollucite, lepidolite, and the borate rhodizite. Pollucite, CsAlSi206, is a hydrated silicate of aluminum and cesium. The concentration of cesium in the earth s crust is estimated to be 3 mg/kg, and in sea water 0.3pg/L. 

I860 Cesium Cs 55 G.Kirchoff, Robert Bunsen Germany Latin word "caesius" meaning "sky blue"... 

Rubidium Rb 37 R. Bunsen, G. Kirchoff Germany Latin word "rubidius" meaning "dark red"... 

Although compounds of sodium and potassium were known in ancient times, it was not until Humphrey Davy s famous electrolytic experiments in 1807 on molten caustic soda and potash that the metals themselves were first isolated. Lithium was first recognized as an alkali metal in various silicate and mica minerals in 1817 (by ArfVedson, who thus named it from the Greek word for stone) and first isolated, again by Davy, in 1818. The discovery of cesium (1860) and rubidium (1861) had to await the development of atomic spectroscopy (by Bunsen and Kirchoff) their names reflect the colors of their dominant spectral lines (Latin caesius, sky blue, and rubidus, deep-red). 

This emission of light from elements was reported as early as the mid-1700s and was later the basis of discovering four elements by Kirchoff and Bunsen in the mid-1800s. However, it was not until the 20th century that the technique really became a useful analytical tool. The first analytical instruments used a spark discharge to provide the energy to excite the atoms so that... 

Cesium was discovered in 1860 by Robert Bunsen and Gustaff Kirchoff. It is used in the most accurate atomic clocks. Cesium melts at 28.4°C (just below body temperature) and occurs in Earth s crust at 2.6 ppm. 

Bunsen was extremely famous in his own time and revered by his students for his part in the development of the technique of spectral analysis numerous other elements were later discovered by chemists using Bunsen and Kirchoff s spectroscope. Those elements include gal-... 

Armed with the empirical knowledge that each element in the periodic table has a characteristic spectmm, and that heating materials to a sufficiently high temperature dismpts all interatomic interactions, Bunsen and Kirchoff invented the spectroscope, an instrument that atomizes substances in a flame and then records their emission spectmm. Using this instmment, the elemental composition of several compounds and minerals were deduced by measuring the wavelength of radiation that they emit. In addition, this new science led to the discovery of elements, notably caesium and mbidium. 

We start with the observations of Kirchoff and Bunsen in Germany in 1859. They observed the bright line spectra for many alkali and alkaline-earth metal-based salts and are credited with the discovery of spectro-chemical analysis. The so-called principal atomic emission series for the common alkali metals is shown in Fig. 4.66. Note that these older atomic spectra are calibrated in terms of wave number, denoted by v, of the emitted radiation whose units are in reciprocal centimeters (denoted by cm ). 

Original paper on spectroscopy by Kirchoff and Bunsen in Annalen der Physik und der Chemie (1860)... 

Figure 6 Kirchoff and Bunsen s spectroscope (A) a tx)x, blackened interior (B) and (C) small telescopes, (B) contains a metal sheet with slit, replacing the eye-piece (D) light source in front of the slit, Bunsen burner and (E) platinum wire for holding material to be examined (F) a hollow glass prism filled with carbon disulfide (G) tumable mirror. (From Kirchoff and Bunsen (1860) Poggendorfs Annalen 110 160.)...

A few years previously, in 1859, the Germans Gustav Robert Kirchoff and Robert Bunsen had discovered that each element could be made to emit light, which could then be dispersed with a glass prism and analyzed quantitatively." What they also discovered was that every single element gave a unique spectrum... 

By closely studying the work of Kirchoff and Bunsen, Hinrichs found that some of the spectral hne frequencies, those referred to as dark hnes, could be related to the chemistry of the elements through their atomic weights, as well as to their postulated atomic dimensions. The difference between the spectral line frequencies seemed to be inversely proportional to the atomic weights of the elements in question. Hinrichs quoted the values of calcium, where the frequency difference is 4.8 units, and barium, which is chemically similar but has a higher atomic weight and shows a frequency difference of 4.4 units." ... 

Rubidium was first discovered in 1861 by two German chemists, R.W. Bunsen and G. Kirchoff, at the University of Heidelberg, who identified the new element in the lithium mineral lepi-dolite using the spectroscope. Later, the pure metal was prepared in 1928 by Hackspill. 

Rubidium Rb 37 85.47 1861 R. W. Bunsen (Ge.) G. Kirchoff (Ge.) L. rubidius, dark red (discovered with the spectroscope, its spectrum shows red lines)... 

Observationally, little progress had been made. Fraunhofer used a newly produced diffraction grating to resolve the sodium D lines in a Bunsen-bumer flame as early as 1823 and Kirchoff had visually recorded the atomic spectra of many elements by the 1860s. Sadly, lack of suitable detection equipment impeded real progress outside the visible part of the spectrum. 

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