Symbol Co. The element with atomic number 27 and relative atomic mass 58.93, which is in the first row of the transition metals . One isotope, cobalt-60, is frequently used in radiotherapy.
Cobalt shows the typical properties of a transition metal.
It can be found with a number of oxidation numbers. Cobalt blue glass is used in flame tests as it can absorb the yellow light of sodium, allowing the much less intense lilac colour of any potassium present to be seen more clearly. Vitamin B 12 is a cobalt-containing organometallic compound. Co The New Penguin Dictionary of Science 2. Alnico A Dictionary of Science, Oxford University Press 3.