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complex ion

(Encyclopedia)complex ion, charged molecular aggregate (see ion), consisting of a metallic atom or ion to which is attached one or more electron-donating molecules. In some complex ions, such as sulfate, SO4−2, t...

Iliescu, Ion

(Encyclopedia)Iliescu, Ion, 1930–, Romanian political leader, president of Romania (1990–96, 2000–2004). A member of the Communist party from 1953, he held a series of party posts before he was elected a memb...

hydrogen bomb

(Encyclopedia)hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that togethe...

hydrogen cyanide

(Encyclopedia)hydrogen cyanide, HCN, colorless, volatile, and extremely poisonous chemical compound whose vapors have a bitter almond odor. It melts at −14℃ and boils at 26℃. It is miscible in all proportions...

hydrogen fluoride

(Encyclopedia)hydrogen fluoride, chemical compound, HF, a colorless, fuming liquid or colorless gas that boils at 19.54℃. It is miscible with water and is soluble in benzene, toluene, and concentrated sulfuric ac...

hydrogen peroxide

(Encyclopedia)hydrogen peroxide, chemical compound, H2O2, a colorless, syrupy liquid that is a strong oxidizing agent and, in water solution, a weak acid. It is miscible with cold water and is soluble in alcohol an...

hydrogen sulfide

(Encyclopedia)hydrogen sulfide, chemical compound, H2S, a colorless, extremely poisonous gas that has a very disagreeable odor, much like that of rotten eggs. It is slightly soluble in water and is soluble in carbo...

Antonescu, Ion

(Encyclopedia)Antonescu, Ion yôn äntônĕsˈko͞o [key], 1882–1946, Romanian marshal and dictator. He served in World War I and later became chief of staff, but he fell into disfavor with King Carol II because ...

Bratianu, Ion

(Encyclopedia)Bratianu, Ion: see under Bratianu, family. ...

parathyroid glands

(Encyclopedia)parathyroid glands pârˌəthīˈroid [key], four small endocrine bodies, located behind the thyroid gland, that govern calcium and phosphorus metabolism. These four masses of tissue (each about the s...