Phosphorus is a chemical element with the symbol P and the atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus , but because it is highly reactive , phosphorus is never found as a free element on Earth.
了解详细信息:Phosphorus is a chemical element with the symbol P and the atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus , but because it is highly reactive , phosphorus is never found as a free element on Earth.
en.wikipedia.org/wiki/PhosphorusIridium is a chemical element; it has symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group , it is considered the second-densest naturally occurring metal (after osmium ) with a density of 22.56 g/cm 3 (0.815 lb/cu in) as defined by experimental X-ray crystallography .
en.wikipedia.org/wiki/IridiumIridium - Wikipedia
20 小时之前 · Iridium is a chemical element; it has symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group , it is considered the second …
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