C 28 superatom analogue of sp 3 carbon atom Suggests T d C 28 H 4 Nature (1987) Support C 28 U tetravalent (Smalley and coworkers) C 28 H 4 Sussex NNC C 32 C 28 Sussex NNC C 24 Sussex NNC No C 22 closed cage is possible! Sussex NNC C 20 C 28 H 4 C 50 Cl 10 was isolated in 2004 C 28 H 4 C 28 Moses Gombergs Free Radical (1901) triphenyl methyl CPh 3 -CPh 3 . CPh 3 +. CPh 3 Moses Gombergs Free Radical (1901) triphenyl methyl CPh 3 -CPh 3 . CPh 3 +. CPh 3 I wish to reserve this field for myself Moses Gomberg 1901 Exxon Data Cox et al JACS (1988) Sussex NNC Assignment Moses Gombergs Free Radical (1901) triphenyl methyl CPh 3 -CPh 3 . CPh 3 +. CPh 3 Moses Gombergs Free Radical (1901) triphenyl methyl CPh 3 -CPh 3 . CPh 3 +. CPh 3 I wish to reserve this field for myself Moses Gomberg 1901 C n+2 rule (4n+3)-1 rule yields 11, 15, 19, 23 C 15 + C 19 + C 23 + Mass spectrum of carbon in which C 60 and C 70 were first recognised as special Sussex NNC Rice Sussex NNC Rice David Jones in a fun article published under the pseudonym of Daedalus in the New Scientist (1966) pointed out that a sheet of hexagons no matter how large could only close if there were exactly 12 pentagons interspersed The Pentagon Isolation Rule (PIR) C 60 is the smallest fullerene that can avoid abutting pentagons Sussex NNC In 1986 the PIR also explained the strength of C 70 as C 62, C 64, C 66 and C 68 must have abutting pentagons Sussex NNC In 1986 the PIR also explained the strength of C 70 as C 62, C 64, C 66 and C 68 must have abutting pentagons Mass spectrum of carbon in which C 60 and C 70 were first recognised as special Sussex NNC Rice C 70 Mass spectrum of carbon in which C 60 and C 70 were first recognised as special Sussex NNC Rice C 50 C 40 C 32 Exxon Data Cox et al JACS (1988) Sussex NNC Assignment Exxon Data Cox et al JACS (1988) C 20 ? Sussex NNC Assignment C 28 superatom analogue of sp 3 carbon atom Suggests T d C 28 H 4 Nature (1987) Support C 28 U tetravalent (Smalley and coworkers) C 28 H 4 Sussex NNC NB Paquettes Group had synthesised Dodecahedrane C 20 H 20 in 1982, three years before the discovery of C 60 With hindsight C 20 H 20 can be recognised as the fully hydrogenated derivative of C 20 the smallest possible and least stable fullerene Kroto and Walton Chem Phys Letts 1993 C 24 H 12 C 32 H 2 C 36 H 12 C 50 H 10 predicted to be stable 1993 Sussex NNC The Oddfellas ? C 20 ? Sussex NNC C 20 ? Sussex NNC NB Paquettes Group had synthesised Dodecahedrane C 20 H 20 in 1982, three years before the discovery of C 60 With hindsight C 20 H 20 can be recognised as the fully hydrogenated derivative of C 20 the smallest possible and least stable fullerene NB Paquettes Group had synthesised Dodecahedrane C 20 H 20 in 1982, three years before the discovery of C 60 With hindsight C 20 H 20 can be recognised as the fully hydrogenated derivative of C 20 the smallest possible and least stable fullerene Moses Gombergs Free Radical (1901) triphenyl methyl CPh 3 -CPh 3 . CPh 3 +. CPh 3 C 50 H 10 Sussex NNC Rice Sussex NNC Exxon Data Cox et al JACS (1988) Sussex NNC Assignment Exxon Data Cox et al JACS (1988) Sussex NNC Assignment BuckyWorld Sussex NNC