In this video we will deal with the real and ratey-procal lattices of crystals and in particular with the BCC lattice. Each crystal consists of a regular arrangement of atoms which determine its lattice structure. These can be divided into 14 previous lattices. It is important to know that the displayed poles are no atoms but dots of the previous lattice. The base and lattice are the smallest repeating unit of the atoms. If that structure we can construct the whole crystal. In our case it is the BCC lattice. This is a simple cubic lattice with fluid dots in which trace of body centered, red dot. This lattice is banned by the vectors A1, A2 and A3, the so-called lattice vectors. With them you can reach any point in the crystal. From this new point the lattice is the same as before. The BCC lattice contains two lattice points. The points in the corners are shared with eight other cells, while the middle dot is contained as a whole. Consequently this is not the smallest unit of the crystal and it is therefore termed conventional unit cell. It is used because of its vividness. From the lattice vector the primitive unit cell can be constructed. This smallness enclosed volume of a crystal and contains only one lattice point. Because each corner is also divided by eight other cells. They form a group dice. To describe interactions, waves, for example, light and lattice vibrations, the red tip vocal lattice is used. This is achieved by a Fourier transformation. Physically one changes from the position space in the momentum space, which simplifies many calculations. The red tip vocal lattice vectors can be calculated by means of the real lattice vectors. Here we get again three vectors with rigid unit cell and thus the whole red tip vocal crystal can be set up. Once more we get a distorted cube. For clarity a conventional unit cell is used in this case. Of course this unit cell must be built with the lattice vectors. As one can easily see, we are dealing with the FCC lattice, which consists of a cubic lattice and which has another lattice point in the center area. This conventional unit cell contains four lattice points. Now we have to assume that the FCC lattice is an FCC lattice narrative vocal space.