<p><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:14px">Examination of the solid state infrared spectra of the tetramethylammoniumcation in salts shows correlation of infrared spectral properties with C&ndash;H&middot;&middot;&middot;X hydrogen bonding and crystal habits in these tetramethylammonium salts. The IR predicted crystal habits are comprised by experimental and theoretical data. A good relation between three data has been found. The C&ndash;H stretching region characteristic hydrogen bonding shifts in the above salts. In this research three complexes of tetramethylammoniumcation have been synthesized and the structures of them have been analyzed by correlation of vibrational data with crystal structures. These correlation shows that crystal symmetry (Tetrahedral), cation distortion (undistorted), site symmetry (D₂d), unite cell symmetry (D₄h⁷) for (CH₃)₄NPF₆ and crystal symmetry (Tetrahedral), cation distortion (distorted), site symmetry (D₂d), unite cell symmetry (D₄h⁷) for (CH₃)₄NOH and crystal symmetry</span></span></p> <p><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:14px">(Tetrahedral), cation distortion (undistorted), site symmetry (D₂d), unite cell symmetry (D₄h⁷) for (CH₃)₄NF.</span></span></p>