The chlorination of ferrocene at 900°C yields very interesting carbon hollow nanospheres (CHNSs) with diameters of ∼50−150 nm and ∼12−25 nm thick walls. X-ray energy-dispersive spectroscopy shows no traces of chlorine or iron and the π*/σ* ratio of the carbon bonding was quantified by electron energy-loss spectroscopy with 80% sp2 (100% sp2 for pure graphite). Energy-filtered transmission electron microscopy has been used to establish the hollow nature of the CHNSs by thickness mapping. Electron energy loss spectroscopy, high-resolution TEM, and Raman microspectroscopy techniques have stated that the CHNS carbon walls are composed of disordered and independent curved graphene nanoflakes ∼3−4 nm long that tend to graphitize with longer reaction times.