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Hydroxyapatite (IMA name: hydroxylapatite [5]) (Hap, HAp, or HA) is a naturally occurring mineral form of calcium apatite with the formula Ca 5 (PO 4) 3 (OH), often written Ca 10 (PO 4) 6 (OH) 2 to denote that the crystal unit cell comprises two entities. [6] It is the hydroxyl endmember of the complex apatite group.
As such, soil type plays a role, because it will affect the water content of the environment. For example, some soils, like clay soils, retain water better than others, like sandy or silty soils. Further, acidic soils are better able to dissolve the inorganic matrix of hydroxyapatite than basic soils, thus accelerating the disintegration of ...
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
The following compounds are liquid at room temperature and are completely miscible with water; ... acetic acid: 64-19-7 (CH 3) 2 CO: acetone: 67-64-1 CH 3 CN:
Fluorapatite (or fluoroapatite) is more resistant to acid attack than is hydroxyapatite; in the mid-20th century, it was discovered that communities whose water supply naturally contained fluorine had lower rates of dental caries. [14] Fluoridated water allows exchange in the teeth of fluoride ions for hydroxyl groups in apatite.
Amorphous calcium phosphate in combination with casein phosphopeptide has been used as a dental treatment to treat incipient dental decay. ACP sees its main use as an occluding agent, which aids in reducing sensitivity. Studies have shown that it does form a remineralized phase of hydroxyapatite consistent with the natural enamel.
In modern times, water is sometimes called the universal solvent, because it can dissolve a large variety of substances; more than any other liquid. [14] This is due to its chemical polarity and amphoterism. [citation needed] The old remark "spit is the universal solvent" satirizes the idea. [15]
Solubility equilibrium is a type of dynamic equilibrium that exists when a chemical compound in the solid state is in chemical equilibrium with a solution of that compound. The solid may dissolve unchanged, with dissociation, or with chemical reaction with another constituent of the solution, such as acid or alkali.