Chemical element cubic centimeter (g/cm). Since several elements are gases at commonly encountered temperatures, their densities are usually stated for their gaseous forms; when liquefied or solidified, the gaseous elements have densities similar to those of the other elements. When an element has allotropes with different densities, one representative allotrope is typically selected in summary presentations, while densities for each allotrope can be stated where more detail is provided. For example, the three familiar allotropes of carbon (amorphous carbon, graphite, and diamond) have densities of 1.8–2.1, 2.267, and 3.515 g/cm, respectively. The elements studied to date as solid samples have eight kinds
Chemical oscillator the consuming pathway. Different theoretical models for this type of reaction have been created, including the Lotka-Volterra model, the Brusselator and the Oregonator. The latter was designed to simulate the Belousov-Zhabotinsky reaction. A Belousov–Zhabotinsky reaction is one of several oscillating chemical systems, whose common element is the inclusion of bromine and an acid. An essential aspect of the BZ reaction is its so-called "excitability" — under the influence of stimuli, patterns develop in what would otherwise be a perfectly quiescent medium. Some clock reactions such as the Briggs–Rauscher reactions and the BZ using the chemical ruthenium bipyridyl as catalyst can