Final answer:
Lanthanum oxybromide and Gadolinium oxysulfide are classified as rare earth phosphors, as they contain lanthanide elements, Lanthanum and Gadolinium respectively, which are used in a variety of applications, including medical imaging.
Step-by-step explanation:
Among the rare earth phosphors, lanthanides like Lanthanum and Gadolinium are often used. Lanthanum, with atomic number 57, is the first element in the lanthanide series, which runs from lanthanum (La) through lutetium (Lu), consisting of elements 57-71. Gadolinium, with atomic number 64, is another lanthanide, found later in the series. Both of these elements play roles in various applications due to their unique properties. Lanthanides are used extensively in devices for numerous purposes, including optical devices like night vision goggles, in petroleum refining processes, and to create specialized alloys.
Lanthanum oxybromide and Gadolinium oxysulfide are indeed classified as rare earth phosphors due to their inclusion of lanthanide elements. These compounds are critical for their ability to convert energies like X-rays into visible light in medical imaging devices and other technologies where phosphorescence is required.