Boron carbide as the typical icosahedron boride orthorhombic crystalline structure of the complex hexahedral structure is main of boron carbide crystal structure and crystal lattice of the six-party diamond as the main clusters containing icosahedron radicals, covalent bond to these groups cluster, and three atoms link on the rhombohedral diagonal structure of B4C is widely agreed that in a B11C icosahedron and a C - B - C atomic chain structure consisting of a B C two atoms in the 20 surface and atomic chain substitute each other, so the boron carbide in carbon mass fraction 8% 20% between many stable isomers (such as B13CB12C3 B4C, etc.)