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Yttrium3Y3988.9059 4.472g/cm1522.

-238 .

,. (),.

().

[Xe]5d6s+3+2La.

(Rare earth) .

rare earth elementB213957~7117RE .

15LnShPNPShnYuGTDHurDi.

15 .

LaCe(Pr)(Nd)(Pm)(Sm)(Eu)(Gd)(Tb)(Dy)(Ho)(Er)(Tm)(Yb)(Lu)15.