A D6Rank3Tensor is a third rank tensor with
D6 point group symmetry. The argument d14is a
real number. The first integer in the argument name is a space
index (1, 2, or 3) and the second is a Voigt index (1 through 6).
Figure 6.143. Structure of a D6 Third Rank Tensor
Structure of a D6 rank 3 tensor. For an explanation of
the symbols, see Figure 6.57.