20
 Li-Hua Gan, Journal of Chemical Education, 85(3), 444, 2008.
C                     -1.972483    0.237749    0.109713
C                     -1.536988    0.233933   -1.241853
C                     -0.871835   -0.996845   -1.485078
C                     -0.896244   -1.753691   -0.283833
C                     -1.576482   -0.990670    0.701801
C                     -1.297136    1.288361    0.785376
C                     -0.444252    1.933858   -0.148606
C                     -0.592489    1.282186   -1.401502
C                      0.656395    0.699264   -1.743396
C                      0.483748   -0.709255   -1.795048
C                      1.297136   -1.288361   -0.785377
C                      0.444252   -1.933859    0.148606
C                      0.592488   -1.282187    1.401502
C                     -0.656396   -0.699265    1.743396
C                     -0.483751    0.709254    1.795050
C                      1.576483    0.990670   -0.701802
C                      1.972483   -0.237750   -0.109713
C                      0.896246    1.753692    0.283833
C                      0.871837    0.996846    1.485078
C                      1.536987   -0.233933    1.241853