Figure 1598 shows the projection-diffraction symmetry of the [1-100] CBED pattern of a T1 (Al₂CuLi) crystal. [1] The pattern symmetry from such a crystal in the [1-100] direction is 2mm. However, this diffraction symmetry does not show perfect 2mm symmetry due to slight misalignment of the second condenser aperture.

[1] Kenneth S. Vecchio and David B. Williams, Convergent Beam Electron Diffraction Analysis of the T1 (Al2CuLi) Phase in Al-Li-Cu Alloys, Metallurgical Transactions A, 19A, 1988-2885, (1988).