Erbium nuclear properties

Given the greater nuclear charge of the succeeding elements, however, and these structures become stable. (In the case of erbium the three additional nuclear charges of lutecium are necessary before this particular erbium kernel structure becomes stable.) Thus the following elements derive their properties from the tendency to revert to the stable forms of the key elements. These are called the beta forms, or Ni/3, Pd/3, Er/3, Pt/3, and the subordinate periods are based on these forms, as is apparent in the table, in the same way that the major periods are based on the inert gases. 

The cost of 99.9% erbium metal is about 21/g. Erbium is finding nuclear and metallurgical uses. Added to vanadium, for example, erbium lowers the hardness and improves workability. Most of the rare-earth oxides have sharp absorption bands in the visible, ultraviolet, and near infrared. This property, associated with the electronic structure, gives beautiful pastel colors to many of the rare-earth salts. Erbium oxide gives a pink color and has been used as a colorant in glasses and porcelain enamel glazes. 

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