Potassium is a chemical element with symbol K (from Neo-Latin kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals.
All of the alkali metals have a single valence electron in the outer electron shell, which is . The type K is commonly found in nuclear applications because of its relative radiation hardness. Maximum continuous temperature is .
Many metallic elements , but not all, become superconducting below K. In intermetallic compounds, transition temperatures even above 20K are Table 10. Transition temperature of elements that become superconducting under atmospheric pressure. In addition, the transition temperature of selected compounds and . In Table we list the most likely values for the transition temperatures of the elements.
These values have been taken, with the exception of the three cases note from EISENSTEIN. Since Arrin is of the order of a typical lattice spacing (a = 3xl0m) which is roughly the same for many elements , Equation 7. Debye temperature ought to be roughly proportional to the speed of sound.