The observed properties and diffraction data for a diamond-like carbon phase that graphitizes at room temperature are shown to be consistent with predictions for "rectangulated diamond" carbon phases. These phases contain eclipsed sp3 carbon layers having the intra-layer connectivity of graphite - just like the case for hexagonal diamond. However, in contrast with known diamond polytypes, these phases contain four-carbon rings of the type found in cyclobutane and in the bridges between cages in C60 polymers.

http://dx.doi.org/10.1016/S0379-6779(97)81165-4