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protactinium

(Encyclopedia)protactinium prōˌtăktĭnˈēəm [key], radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600℃; b.p. 4,026℃; sp. gr. 15.37 (calcula...

organic chemistry

(Encyclopedia)organic chemistry, branch of chemistry dealing with the compounds of carbon. While it is only the fourteenth most common element on earth, carbon forms by far the greatest number of different compound...

Plücker, Julius

(Encyclopedia)Plücker, Julius yo͞oˈlyo͝os plüˈkər [key], 1801–68, German mathematician and physicist. He became professor of mathematics (1836) and of physics (1847) at the Univ. of Bonn. He is known for h...

Chongqing

(Encyclopedia)Chongqing cho͞ongˈkĭngˈ [key], city and independent municipality, 592 sq mi (1,534 sq km), in SE ...

hardening

(Encyclopedia)hardening, in metallurgy, treatment of metals to increase their resistance to penetration. A metal is harder when it has small grains, which result when the metal is cooled rapidly. Sometimes small ar...

Anhui

(Encyclopedia)Anhui or Anhwei both: änˈhwāˈ [key], province, c.55,000 sq mi (142,450 sq km), E central China. Hefei is the capital. Anhui may be divided into two climatic areas. The north...

Copiapó

(Encyclopedia)Copiapó kōpyäpōˈ [key], city (1990 est. pop. 79,268), capital of Atacama region, N central Chile, on the Copiapó River. An industrial city at the southern edge of the Atacama Desert, Copiapó ha...

Ibaraki

(Encyclopedia)Ibaraki ēbäˈräkē [key], prefecture, 2,352 sq mi (6,092 sq km), central Honshu, Japan. ...

Anaconda, city, United States

(Encyclopedia)Anaconda ănəkŏnˈdə [key], city (2020 pop. 9,162), seat of Deer Lodge co., SW Mont.; inc. 1887. Marcus Daly chose this place (1883) for the Anaconda Copper Mining Company's ...

patina

(Encyclopedia)patina pătˈənə [key], coating of carbonate of copper on articles of copper or bronze, formed after long exposure to a moist atmosphere or burial in the earth. Although commonly green, patina varie...