Is Ln(3+) compounds coloured or colourless

Dear Student,

The Ground state Electronic Configuration of Ln³⁺ is [Kr]³⁶4d¹⁰.

Now, as we can see that there are no unpaired electrons in Ln³⁺, therefore it is colourless. Because any compound will impart some colour when it contains even one number of unpaired electrons.

Hope this information clears your doubts about the topic.

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