There are two different common crystalline forms of carbon - diamond and graphite. A less common form called fullerene, C60, also exists. Different forms of the same element in the same physical state are called:

16. in a reaction that has reached equilibrium, a. the forward and reverse reactions are occurring at the same rate. b. the reactants and products are in equal concentrations. c. the forward reaction has gone further than the reverse reaction. d. there are equal numbers of atoms on both sides of the equation. e. a, b, and d are correct.