Cesium

General information

Cesium is a silver-white soft alkaline metallic element (symbol Cs, atomic number 55). It is used industrially in photoelectric cells and as a catalyst for the hydrogenation of some organic compounds. The natural resonance frequency of excited caesium atoms forms the basis of the measurement of time in atomic clocks, and the international definition of a second is the interval occupied by a specific number of cycles, specifically the duration of 9 192 631 770 cycles of radiation corresponding to the transition between two energy levels of the ¹³³ cesium atom. Radioactive ¹³⁷ cesium is a by-product of nuclear energy production. ¹³¹ Cesium has been used to treat prostate cancer in brachytherapy. Oral cesium chloride has been used to treat cancers in complementary medicine, on the basis of the hypothesis referred to as “high pH cancer therapy”, but there is no evidence of efficacy [ ]. Its adverse effects include gastrointestinal distress, hypotension, numbness or tingling of the lips, hypokalemia, hypomagnesemia, and prolongation of the QT interval and cardiac dysrhythmias.