Can lanthanum (Z=57) ion exist +4 Oxidation state?

Lanthnum(Z=57) has electronics configuration [Xe]5d1 6s2  and forms La3+ ion by the removal of 3 electrons (two electrons from 6s and one electron from 5d) leaving behind stable noval gas configuration. To form  La4+ ion stable noble gas configuration will have to be distributed which is impossible. Hence La4+  Ion cannot exist.

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