Number of colourless lanthanoid ions among the following is . Eu3+, Lu3+, Nd3+, La3+, Sm3+
Answer
2
Solution
Colour of Ln3+ ions comes from f–f transitions, so 4f0 and 4f14 ions are colourless.
La3+: 4f0 (colourless); Lu3+: 4f14 (colourless)
Nd3+: 4f3, Sm3+: 4f5, Eu3+: 4f6 (coloured)
Hence 2.
Answer: 2