Patent Number: 054019753
Section: summary

BACKGROUND OF THE INVENTION The present invention relates to a molecular structure of carbon atoms and a cluster of carbon molecules and a method for constructing the same. As conventional molecular structures of carbon atoms, there are known diamond, graphite and soot. Recently there are further known a series of buckminsterfullerene molecules found by H. W. Kroto et al. and described in Nature, Vol. 318, pp. 162-163, 1985, and carbon nano-tubes found by Iijima and described in Nature, Vol. 354, pp. 56-58, 1991. Each of these carbon molecules is constructed in the form of a carbide compound. As proposed by David Vanderbilt and J. Tersoff and described in Phys. Rev. Lett., Vol. 68, pp. 511-513, 1992, there is known the fact that a material constituted by carbon atoms arranged on a periodic minimum plane exists theoretically. In the molecular structures proposed in the prior art, mechanically sufficient strength cannot be obtained and hence there arises a problem that the molecular structures cannot be applied to any dynamic mechanical element. It has been thought of that a structure in which carbon atoms are arranged in the form of a torus is suitable for solution of the problem. There has not been, however, any proposal of a stable structure of a cluster of carbon atoms arranged in the form of a torus. On the other hand, although a cluster of carbon atoms having a cylindrically helical structure has been proposed, there has not been any proposal of a helical structure having mechanically sufficient strength. SUMMARY OF THE INVENTION An object of the present invention is to provide a structure having mechanically sufficient strength and also thermodynamical stability at high temperature obtained by giving novel topological properties to a cluster of carbon atoms to thereby make it possible to be adapted to a dynamic mechanical element, and also provide a method for constructing the structure. In addressing the foregoing object, according to the present invention, a cluster of carbon atoms is formed by arranging carbon atoms stably in the form of a torus so that novel topological properties are given to carbon atoms. According to the present invention, a plurality of sixfold rings each consisting of six carbon atoms are arranged in the form of a torus, whereafter these sixfold rings are partially replaced by fivefold and sevenfold rings to obtain a stable structure. That is, a part of the outer wall surface of a torus constituted by a plurality of sixfold rings and a part of the inner wall surface of the torus are replaced by fivefold rings and sevenfold rings respectively to obtain a stable structure. Because the cluster of carbon atoms according to the present invention is toroidal, mechanically sufficient strength can be obtained so that a dynamic mechanical element can be formed by using the hole of the torus and the inside of the torus.