Calcium carbonate equilibrium pressure must exceed total atmospheric pressure of 101 kPa, which happens at 898 °C. Calcium carbonate is poorly soluble in pure water (47 mg/L at normal atmospheric CO partial pressure as shown below). The equilibrium of its solution is given by the equation (with dissolved calcium carbonate on the right): where the solubility product for [Ca] [CO] is given as anywhere from "K" = 3.7×10 to "K" = 8.7×10 at 25 °C, depending upon the data source. What the equation means is that the product of molar concentration of calcium ions (moles of dissolved Ca per liter of solution)
Calcium channel opener Calcium channel opener A calcium channel opener is a type of drug which facilitates ion transmission through calcium channels. An example is Bay K8644, which is an analogue of nifedipine that specifically and directly activates L-type voltage-dependent calcium channels. In contrast to Bay K8644, which is not for clinical use, Ambroxol is a frequently used mucolytic drug that triggers lysosomal secretion by mobilizing calcium from acidic calcium stores. This effect does most likely not occur by a direct interaction between the drug and a lysosomal calcium channel, but indirectly by neutralizing the acidic pH within lysosomes. Calcium permeable ion channels