Potassium-bearing minerals, reaction

In order to date a potassium-bearing mineral by the 40Ar/3 >Ar method the sample is first irradiated by energetic neutrons in the core of a nuclear reactor (Faure and Mensing 2005). The neutrons interact with the nuclei of atoms and transform them into nuclei of Ar by a nuclear reaction of the form ... 

A very rapid oxidative disintegration of chromium-bearing minerals, rocks and alloys is obtained by fusing or sintering the finely pulverized material with potassium bifluoride (platinum spoon). Potassium chromate results and may be detected by means of the diphenylcarbazide reaction. The fluoride disintegration is particularly recommended for the detection of chromium in steels or special alloys, which are likely to contain molybdenum. The latter, in the form of molybdate ions, reacts with diphenylcarbazide to yield a red-violet color and thus impairs the test for chromium. However, the fluoride method yields no M0O4" ions, but instead complex [M0O3F2] ions, which do not react with diphenylcarbazide. 

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