Lutetium tantalate

Lutetium tantalate is a chemical compound of lutetium, tantalum and oxygen with the formula LuTaO4. With a density of 9.81 g/cm3, this mixed oxide compound is the densest known white stable material. (Although thorium dioxide ThO2 is also white and has a higher density of 10 g/cm3, it is radioactively unstable; while not radioactive enough to make it unstable as a material, even its low rate of decay is still too much for certain uses such as phosphors for detecting ionising radiation.) The white color and high density of LuTaO4 make it ideal for phosphor applications, though the high cost of lutetium is a hindrance.

This keyword could refer to multiple things. Here are some suggestions: