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Silver chloride |
| Silver chloride | |
|---|---|
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| IUPAC name | Silver(I) chloride |
| Other names | Silver chloride; cerargyrite; chlorargyrite; horn silver |
| Identifiers | |
| CAS number | 7783-90-6 |
| RTECS number | VW3563000 |
| Properties | |
| Molecular formula | AgCl |
| Molar mass | 143.32 g mol−1 |
| Appearance | White Solid |
| Density | 5.56 × 103 kg m−3 |
| Melting point |
457 °C |
| Boiling point |
1550 °C |
| Solubility in water | 52 × 10−6 g/100 g at 50 °C |
| Structure | |
| Crystal structure | halite |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−127.01 kJ mol−1 |
| Standard molar entropy S |
96.25 J mol−1 K−1 |
| Hazards | |
| MSDS | Salt Lake Metals |
| NFPA 704 |
 0
2
0
|
| Related compounds | |
| Other anions | silver(I) fluoride, silver bromide, silver iodide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Silver chloride is a chemical compound with the chemical formula AgCl. This white crystalline solid is well known for its low solubility in water (this behavior being reminiscent of the chlorides of Tl+ and Pb2+). Upon illumination or heating, silver chloride converts to silver (and chlorine), which is signalled by greyish or purplish coloration to some samples. Also when silver chloride is left in the sun it turns purple. AgCl occurs naturally as a mineral chlorargyrite.
Contents |
The solid adopts the fcc NaCl structure, in which each Ag+ ion is surrounded by an octahedron of six chloride ligands. AgF and AgBr crystallize similarly.1 However, the crystallography depends on the condition of crystallization, primarily free silver ion concentration. AgCl dissolves in solutions containing ligands such as chloride, cyanide, triphenylphosphine, thiosulfate, thiocyanate and ammonia. Silver chloride reacts with these ligands according to the following illustrative equations:
Most complexes derived from AgCl are two-, three-, and, in rare cases, four-coordinate, adopting linear, trigonal planar, and tetrahedral coordination geometries, respectively.
In one of the most famous reactions in chemistry, addition of colorless aqueous silver nitrate to an equally colorless solution of sodium chloride produces an opaque white precipitate of AgCl:2
This conversion is a common test for the presence of chloride in solution. The solubility product, Ksp, for AgCl is 1.8 x 10−10, which indicates that one liter of water will dissolve 0.000013 grams of AgCl. The chloride content of an aqueous solution can be determined quantitatively by weighing the precipitated AgCl, which conveniently is non-hygroscopic, since AgCl is one of the few transition metal chlorides that is unreactive toward water. Ions that interfere with this test are bromide and iodide, as well as a variety of ligands (see silver halide). For AgBr and AgI, the Ksp values are 5.2 x 10−13 and 8.3 x 10−17, respectively. The silver bromide (slightly yellowish white) and silver iodide (pale yellow) are also significantly more photosensitive than is AgCl.
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