Alkaline earths, history

The differences in condensation history of the three alkaline-earth element fission products allows examination of their radioactivity ratio as a method for determining fractionation. The recent atmospheric... 

The weathering of surface rocks has had a critical role in the chemical evolution of the continental crust for most of the Earth s history. In the presence of air and water, mafic minerals tend to rapidly weather into iron (oxy)(hydr)oxides, clays, and other silicate minerals, and at least partially water-soluble salts of alkalis (sodium and potassium) and alkaline earths (calcium and magnesium). In contrast, quartz in felsic and intermediate igneous rocks is very stable in the presence of surface air and water, which explains why the mineral readily accumulates in sands and other sediments. 

GICs have been first discovered from the reaction of graphite with sulfuric acid more than 150 years ago.30 In the long history of GICs research, a huge number of compounds have been yielded with a large variety of donors and acceptors, in which alkali metals, alkaline earth metals, transition metal chlorides, acids, and halogens are involved as typical intercalates. 

The metal monohydroxides CaOH and SrOH are the simplest monovalent polyatomic derivatives of the alkaline earths. Both CaOH and SrOH have a surprisingly long history in view of their high chemical reactivity. While CaOH and SrOH can only be stored when isolated in rare gas matrices [14], substantial steady-state concentrations exist in a variety of energetic environments. 

Another important feature in the history of REEs was that they all were first extracted in the form of oxides. Chemists of the past used the name earths for oxides of, for instance, magnesium, calcium (cf. alkaline earths ) and applied it (erroneously, as it became clear later) to oxides of the first REEs, yttrium and cerium. Hence the term rare earths . Pure metals were prepared long after the discovery of the corresponding elements. For instance, a series of heavy lanthanides was prepared as pure metals only after the Second World War. Therefore, in our subsequent narration, the term REEs will refer to oxides. 

Like a family history, the elements are arranged in family groups such as noble gas, halogen, metal, rare earth, transitional metal, non-metal, alkali metal, and alkaline earth. Just as genetic analysis helps biologists and physicians to determine a person s make-up, so the grouping of elements into families and groups helps chemists to understand similar properties of different elements. 

Ever since Petersen reported the complexing ability of the crown ether with alkali, alkaline earth and other cations, crown ether became a major subject for researchers. This is due to the fact that crown ether possesses the ability to form complexes with a variety of inorganic salts and also the ability to solubilize these salts in aprotic solvents The complexation between metal cation and crown ether is believed to involve ion-dipole interactions and therefore is similar in nature to ordinary solvation. In addition, crown ether/metal cation complexes can serve as catalysts in reactions involving ionic intermediates. Polymerization of diene with crown ether/metal cation complexes is a typical example of this subject, since this reaction involves ionic intermediates. The detailed information including a brief history, chemical properties of crown ether and its application in the anionic polymerization and copolymerization have been discussed. 

The history of optical emission spectrometry (OES) goes back to Bunsen and KirchhofF, who reported in 1860 on spectroscopic investigations of the alkali and alkaline earth elements with the aid of their spectroscope [1], The elements cesium and rubidium and later on thorium and indium were also discovered on the basis of their atomic emission spectra. From these early beginnings, qualitative and quantitative aspects of atomic spectrometry were considered. The occurrence of atomic spectral lines was understood as unequivocal proof of the presence of these elements in a mixture. Bunsen and KirchhofF in addition, however, also estimated the amounts of sodium that had to be brought into the flame to give a detectable line emission and thereby laid the foundation for quantitative analyses and trace determinations with atomic spectrometry. 

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