Third angle projection

An example of third angle projection is shown in Fig. 20.8 each view showing what would be seen by looking on the near side of an adjacent view. 

Orthographic projection may be first angle or third angle and the system used on a drawing should be shown by the appropriate symbol. 

A similar process, using the Newman projection diagram on the right, which places C2 in front of Cj, and uses Clj as the third atom for the dihedral angles, results in the last two lines of the Z-matrix ... 

Figure 6.4 shows the magnetic field vector B in the molecular Cartesian axes system xyz whose orientation is defined by the polar angles 0 (between B and z) and < ) (between the projection of B on the x-y plane and x). The third dimension of the... 

The second condition is that there must be, at the centre of symmetry, an atom whose diffracting power is very much greater than that of any of the other atoms in the cell. The third is that there must be only one such atom per lattice point in the projected unit cell j this atom is conveniently taken as the origin of the projected cell. In these circumstances, it is certain that the phase angles of all the reflections with respect to the origin are 0°, since the wave from the heavy atom at... 

---