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americium

(Encyclopedia)americium ămərĭˈshēəm [key], artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175℃; b.p. about 2,600℃; sp. gr. 13....

neptunium

(Encyclopedia)neptunium nĕpto͞oˈnēəm [key], radioactive chemical element; symbol Np; at. no. 93; mass number of most stable isotope 237; m.p. about 640℃; b.p. 3,902℃ (estimated); sp. gr. 20.25 at 20℃; va...

neon

(Encyclopedia)neon nēˈŏn [key] [Gr.,=new], gaseous chemical element; symbol Ne; at. no. 10; at. wt. 20.1797; m.p. −248.67℃; b.p. −246.048℃; density 0.8999 grams per liter at STP; valence 0. Neon is a col...

tantalum

(Encyclopedia)tantalum tănˈtələm [key] [from Tantalus], metallic chemical element; symbol Ta; at. no. 73; at. wt. 180.94788; m.p. 2,996℃; b.p. 5,400±100℃; sp. gr. 16.65 at 20℃; valence +2, +3, +4, or +5....

Eleanor of Aquitaine

(Encyclopedia)Eleanor of Aquitaine ăkwĭtānˈ, ăkˈwĭtān [key], 1122?–1204, queen consort first of Louis VII of France and then of Henry II of England. Daughter and heiress of William X, duke of Aquitaine, s...

Eleanor of Castile

(Encyclopedia)Eleanor of Castile kăstēlˈ [key], d.1290, queen consort of Edward I of England and daughter of Ferdinand III of Castile. At her marriage (1254) she brought to Prince Edward the territories of Ponth...

Eleanor of Provence

(Encyclopedia)Eleanor of Provence prôväNsˈ [key], d. 1291, queen consort of Henry III of England. The daughter of Raymond Berengar, count of Provence, she was married to Henry in 1236. She was a vigorous and inc...

Diagoras of Rhodes

(Encyclopedia)Diagoras of Rhodes, ancient Greek athlete, fl. 5th cent. b.c. A boxer and wrester, he won an Olympic championship in 464 b.c. and won numerous times at the Pythian, Isthmian, and Nemean games. Pindar ...

Didymus of Alexandria

(Encyclopedia)Didymus of Alexandria, d. c.396, Greek grammarian and theologian, also called Didymus the Blind. His treatise On the Holy Ghost was translated by St. Jerome, who studied briefly with him. Although Did...

Diogenes of Apollonia

(Encyclopedia)Diogenes of Apollonia ăpəlōˈnēə [key], 5th cent. b.c., Greek philosopher. An eclectic, he reverted to the Milesian tradition of a century earlier in seeking to explain the constitution of all ma...