decipium

Century Dictionary and Cyclopedia

1. n. Chemical symbol, Dp; atomic weight, 106 if the oxid is DpO, or 171 if, as is likely, the oxid is Dp₂O₃. A substance found in the samarskite of North Carolina, and said to be a metallic element intermediate in character between the metals of the cerium and yttrium groups. Its salts are colorless. The acetate crystallizes easily.

Wiktionary

1. n. obsolete Proposed name for a chemical element isolated from samarskite, later found to be a mixture of samarium and other rare earth elements.

GNU Webster's 1913

1. n. (Chem.) A supposed rare element, said to be associated with cerium, yttrium, etc., in the mineral samarskite, and more recently called samarium. Symbol Dp. See samarium.