a nonmetallic univalent element; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite

• 一种非金属单价元素，通常为黄色的刺激性有毒易燃气体，氧化性极强，从萤石、冰晶石或氟磷灰石中回收