a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite
造句
用作名詞(n.)
It is a compound of aluminum, silica and fluorine. 它是鋁、硅和氟的化合物。
Fluorin can avoid brown striation and whiten skins. 氟能消除褐色斑,使皮膚變白。