ABSTRACT
Polyyne Gas Molecules? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 16.9 Laboratory Carbon Condensation Experiments. . . . . . . . . . . . . . . . 357 16.10 A New Carbyne Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 16.11 Circumstellar Dust. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 16.12 Interstellar Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 16.13 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
This paper on natural carbynes adopts a strictly mineralogical approach that will be necessary to appreciate the information available on these
peculiar carbons. Ternary classification of elemental carbons using the sp-hybridized carbon bond character, sp3 (cubic diamond), sp2 (hexagonal graphite) and sp1 (linear carbynes), creates ‘‘chemical’’ order [1] to focus discussions. It presumes equality among elemental carbon solids in a mineralogical sense when, for example, considering carbon allotropy rather than polymorphy that is, strictly speaking, incorrect. Mineralogists accept only two carbon allotropes (hexagonal graphite and cubic diamond) each with a thermodynamic pressure-temperature (P-T ) stability field that could ‘‘trespass’’ on each other’s stability field for kinetic factors delaying an equilibrium transformation. Hence, orthorhombic graphite, cubic graphite (cliftonite), hexagonal diamond (lonsdaleite; carbon-2H), carbynes and fullerenes, are metastable crystalline carbons free of heteroatoms.
