Oxygen isotope ratio cycle likely driven by the Lomagundi carbon isotope excursion. Oxygen isotope ratio cycle Oxygen isotope ratio cycles are cyclical variations in the ratio of the abundance of oxygen with an atomic mass of 18 to the abundance of oxygen with an atomic mass of 16 present in some substances, such as polar ice or calcite in ocean core samples, measured with the isotope fractionation. The ratio is linked to water temperature of ancient oceans, which in turn reflects ancient climates. Cycles in the ratio mirror climate changes in geologic history. Oxygen (chemical symbol O) has three naturally occurring isotopes: O, O,
Isotopes of moscovium Isotopes of moscovium Moscovium (Mc) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was Mc in 2004. There are four known radioisotopes from Mc to Mc. The longest-lived isotope is Mc with a half-life of 0.8 seconds. The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=115. Each entry is a combination for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with