Calcium CH ligand with the bulkier C(CH) ligand on the other hand increases the compound's solubility, volatility, and kinetic stability. Natural calcium is a mixture of five stable isotopes (Ca, Ca, Ca, Ca, and Ca) and one isotope with a half-life so long that it can be considered stable for all practical purposes (Ca, with a half-life of about 4.3 × 10 years). Calcium is the first (lightest) element to have six naturally occurring isotopes. By far the most common isotope of calcium in nature is Ca, which makes up 96.941% of all natural calcium. It is produced in the silicon-burning
Symbol Hence, "outward sign" of something. The meaning "something which stands for something else" was first recorded in 1590, in Edmund Spenser's "Faerie Queene". In considering the effect of a symbol on the psyche, in his seminal essay "The Symbol without Meaning" Joseph Campbell proposes the following definition: "A symbol is an energy evoking, and directing, agent". Later, expanding on what he means by this definition Campbell says: Jared Elisha defined symbolism that is something that stands for another, it can be place, object, or a person Heinrich Zimmer gives a concise overview of the nature, and perennial relevance, of symbols.