Rare Elements in the Earths Crust - Compounds and Contents

Rare Elements in the Earth s Crust - Compounds and Contents 

Determination of the rare-element content in rock samples is a more difficult analytical problem than determination of the main components. The development of optical spectroscopy, X-ray fluorescence analysis, atomic absorption spectrophotometry (AAS), mass spectrometry and other analytical methods from the middle of the 20 century made careful mapping of the composition of the crust possible, even for the rarer elements. The content of each element is given in the corresponding element chapter. 

The year 1912 was memorable for the whole of materials science. As described in Chapter 2, it was in that year that von Laue at the University of Munich discovered that the regular atomic arrangement in crystals can act as a diffraction grating for X-rays. This made it possible to determine the atomic structure of minerals and other 

In 1922 Assar Hadding at the Swedish University in Lund began to use X-ray analysis to determine the composition of minerals. Goldschmidt also rapidly apphed the new technique of X-ray fluorescence analysis and confirmed that Harlan s rule is also vahd for rare elements. 

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