Can two-dimensional mesophases solidify?

We investigate whether the orientational contribution to the free energy of a two-dimensional system of hard rectangular rods will assist in the formation of a solid phase from an anisotropic fluid phase. At a density of 77% of close-packed (where independent evidence exists for a hard-square fluid-solid transition) the orientational pressure and free energy are a small fraction of the corresponding values for the solid phase and furthermore the slope of the orientational pressure versus density acts against the formation of a solid phase. We conclude that a hard-square fluid-solid transition does not automatically imply a corresponding transition for hard rectangles.