Barium was an element on the periodic table.
Alpha Meson phosphors used cosmic rays bombarding a layer of barium to produce light. (TV: The Tomb of the Cybermen [+]Loading...["The Tomb of the Cybermen (TV story)"])
Barium sulphate (PROSE: Cold Fusion [+]Loading...["Cold Fusion (novel)"]) and barium silicate were molecules that contained barium. (AUDIO: The Shadow Heart [+]Loading...["The Shadow Heart (audio story)"])