Two lanthanoids ........... and .......... show +4 oxidation states.

Explanation

To answer the question regarding which two lanthanoids show a +4 oxidation state, we can follow these steps:

### Step 1: Identify the Lanthanoids
Lanthanoids, also known as lanthanides, are a series of 15 chemical elements from lanthanum (La, atomic number 57) to lutetium (Lu, atomic number 71) in the periodic table.

### Step 2: Determine the Oxidation States
Lanthanoids typically exhibit multiple oxidation states, but the most common ones are +3 and +4. The +4 oxidation state is less common among lanthanoids.

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