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
Calcium supplement citrate, calcium gluconate, calcium lactate and calcium phosphate. Vitamin D is added to some calcium supplements. Proper vitamin D status is important because vitamin D is converted to a hormone in the body, which then induces the synthesis of intestinal proteins responsible for calcium absorption. For U.S. dietary supplement and food labeling purposes the amount in a serving is expressed in milligrams and as a percent of Daily Value (%DV). The weight is for the calcium part of the compound - for example, calcium citrate - in the supplement. For calcium labeling purposes 100% of the Daily Value was 1000