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holmium

(Encyclopedia)holmium hōlˈmēəm [key] [Lat.,=Stockholm], metallic chemical element; symbol Ho; at. no. 67; at. wt. 164.93032; m.p. about 1,474℃; b.p. about 2,425℃; sp. gr. 8.78 at 25℃; valence +3. Holmium ...

bromine

(Encyclopedia)bromine brōˈmēn, –mĭn [key] [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2℃; b.p. 58.78℃; sp. gr. of liquid 3.12 at 20℃; density of va...

metallurgy

(Encyclopedia)metallurgy mĕtˈəlûrˌjē [key], science and technology of metals and their alloys. Modern metallurgical research is concerned with the preparation of radioactive metals, with obtaining metals econ...

hydrocarbon

(Encyclopedia)hydrocarbon hīˌdrōkärˈbən [key], any organic compound composed solely of the elements hydrogen and carbon. The hydrocarbons differ both in the total number of carbon and hydrogen atoms in their ...

plutonium

(Encyclopedia)plutonium plo͞otōˈnēəm [key], radioactive chemical element; symbol Pu; at. no. 94; mass no. of most stable isotope 244; m.p. 641℃; b.p. 3,232℃; sp. gr. 19.84 at 20℃; valence +3, +4, +5, or ...

ruthenium

(Encyclopedia)ruthenium ro͞othēˈnēəm [key], metallic chemical element; symbol Ru; at. no. 44; at. wt. 101.07; m.p. about 2,310℃; b.p. about 3,900℃; sp. gr. 12.41 at 20℃; valence commonly +2, +3, +4, +6, ...

xenon

(Encyclopedia)xenon zēˈnŏn [key] [Gr.,=strange], gaseous chemical element; symbol Xe; at. no. 54; at. wt. 131.293; m.p. −111.9℃; b.p. −107.1℃; density 5.86 grams per liter at STP; valence usually 0. Xeno...

ore

(Encyclopedia)ore, metal-bearing mineral mass that can be profitably mined. Nearly all rock deposits contain some metallic minerals, but in many cases the concentration of metal is too low to justify mining the ore...

Freundlich, Erwin Finlay

(Encyclopedia)Freundlich, Erwin Finlay froindˈlĭkh [key], 1885–1964, German astronomer. Freundlich obtained a doctorate in mathematics at Göttingen, then joined the Royal Observatory at Berlin, where he worked...

Hewitt, Peter Cooper

(Encyclopedia)Hewitt, Peter Cooper hyo͞oˈĭt [key], 1861–1921, American scientist and inventor, b. New York City; son of Abram S. Hewitt and grandson of Peter Cooper. He invented a mercury-vapor lamp and a merc...