Gadolinium hydride is a dark gray solid that is chemically stable but breaks down at high temperatures. It can be prepared by direct reaction of metal gadolinium with hydrogen gas, and the crystal structure is hexagonal and most densely packed. Gadolinium hydride is used in the nuclear energy industry as a cladding material for fuel rods, providing protection and cooling. In addition, it can also be used as an additive to rare earth metal alloys to enhance the strength and toughness of the alloys. Gadolinium hydride can also be used in catalysts, hydrogen storage materials and other fields. However, gadolinium hydride is toxic and can cause irritation to the human body, so proper safety measures need to be taken when using and handling it. In short, gadolinium hydride is a compound with many potential applications.