An inter metallic compound having the chemical formula A₃B, where A represents a transition element and a crystal structure in which the B atoms are located as the corners and in the corner of a cubic unit cell, while the A atoms are arranged in pairs on the cube faces. Also known as A 15 compound. Many A 15 compounds exhibits the phenomena of super conductivity at relatively at high temperature in the neighboured of 20k (-424⁰F) and in high magnetic fields of the order of several tends of tesla (several hundred kilogauss). High temperature high field super conductivity has a number of important technological applications and is a challenging fundamental research in condensed matter physics. The A 15 compounds crystallize in a structure in which the unit cell, the repeating unit of the crystal structure, has the overall shape of a cube. The B atoms are located at the corners and in the centre of the cube, while the A atoms are arranged in pairs on the cube faces. A special charactistics of the A 15 crystal structure is that the A atoms form mutually orthogonal linear chains that run through the crystal lattice.

The extra ordinary super conducting properties of the A 15 compounds are believed to be primarily associated with these linear chains of transition-elements an atom. Processes have been developed for preparing multifilament super conductor A 15 compound, such as Nb₃Sn embedded in a non superconducting copper matrix. Super conducting wires can be used in electric power transmission lines and to wind electrically lossless coils (solenoids) for super conducting electrical machinery (motors and generators) and magnets. Super conducting magnets are employed to produce intense magnetic fields for laboratory research, confinement of high temperature plasmas in nuclear fusion research, bending beams of charged particles in accelerators, levitation of high speed trains, mineral separation and energy storage.