n. Symbol Pd A soft, ductile, lustrous gray-white, tarnish-resistant, metallic element occurring naturally with platinum, especially in gold, nickel, and copper ores. Because it can absorb large amounts of hydrogen, it is used as a purification filter for hydrogen and a catalyst in hydrogenation. It is alloyed for use in electric contacts, jewelry, nonmagnetic watch parts, and surgical instruments. Atomic number 46; atomic weight 106.4; melting point 1,554.8°C; boiling point 2,963°C; specific gravity 12.02 (20°C); valence 2, 3, 4. See Periodic Table. [From PALLAS (discovered at the same time as the element).] |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.