Inorganic Substances Showing Luminescence:

As declared earlier, only lanthanides and uranium compounds show fluorescence in solution therefore these ions are analysed straight without use of any of the organic or inorganic reagents. Inside lanthanides Ce, Pr, Nd show fluorescence along with electronic transitions from 5d to 4f shells e.g. for Ce (III) λ _ex. = 260nm, λ _{e m}. = 350 nm.  In dilute solutions, the spectrum is extremely sharp due to transitions of f-electrons. The uranium compounds display natural fluorescence at 520-620nm. U (VI) is extracted along with tributylphosphate and is back washed with Na₃PO₄ and the resulting fluorescence is measured. In presence of H₃PO₄, the intensity of fluorescence is enhanced.