Potassium chloride | |
---|---|
Names: | potassium chloride muriate of potash MOP |
Formula: | KCl |
SMILES: | [Cl-].[K+] |
Molar mass: | 74.551 g/mol |
Density: | 1.988 g/cm3 |
Crystal system: | cubic a=6.29294 Å, b=6.29294 Å, c=6.29294 Åα=90°, β=90°, γ=90° |
Shapes: |
|
Color: | colorless |
Melting point: | 776 °C1,049.15 K <br />1,428.8 °F <br />1,888.47 °R <br /> |
Boiling point: | 1420 °C1,693.15 K <br />2,588 °F <br />3,047.67 °R <br /> |
Refractive index: | 1.4902 |
Magnetic properties: | diamagnetic χ=-3.90 · 10-5cm³/mol |
Radiation properties: | slightly radioactive |
Stability: | stable |
Hardness: | strong (2.5 on Moh's scale) |
Toxicity: | non-toxic LD50=2600mg/kg |
Description
Inorganic compound, salt of alkaline metal potassium and inorganic hydrochloric acid. Doesn't form water hydrates.
Minerals
Occurs in nature as sylvite, sylvinite and carnallite minerals.
Where to buy
Can be bought in fertilizers store (as "muriate of potash") and grocery store (as "salt with a reduced sodium content", mixture with sodium chloride in 1:1 ratio).
Precursors
Reaction between potassium hydroxide or carbonate and hydrochloric acid
Chemical equation:
100.00
g of potassium chloride а 75.26
g of potassium hydroxide or 92.69
g of carbonate and 128.70
g of 38%
hydrochloric acid is required.Add acid to the flask, then add small parts of potassium compound with stirring until it will totally dissolve or, if you use carbonate, until carbon dioxide emission will stop. After reaction will stop, filter the solution and use it for crystal growing.
Recrystallization of "salt with a lower sodium content"
Add potassium and sodium chlorides mixture to the flask with boiling water until solution become saturated. Then filter out the solution and cool slowly. Excess of compound precipitates as a crystalline precipitate, most of impurities remain in the solution.
Separate this precipitate from the stock solution, and repeat this process for several times, use the same solution at each next step. Finally, the precipitated compound is used for crystal growing.
Influence of temperature
Temperature increase leads to changing crystals shape to long thin needles.
Influence of impurities
The technical compound impurities slightly affect a growth of crystals. For compound purifying filter the solution through a dense filter, and then recrystallize compound several times.
Excess of sodium chloride more than 40% of crysal mass leads to polycrystals forming. But, unlike sodium chloride, excess of urea does not affect to crystal shape at all.
Storage conditions
Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.
Solubility
Temperature | гр/100,00 гр water | гр/100,00 гр ethanol | гр/100,00 гр methanol | гр/100,00 гр glycerol | гр/100,00 гр furfural | гр/100,00 гр ethylene glycol | гр/100,00 гр formic acid 95% | гр/100,00 гр acetic acid | гр/100,00 гр propanol | гр/100,00 гр hydrazine | гр/100,00 гр acetamide | гр/100,00 гр dimethylformamide | гр/100,00 гр N-methylformamide | гр/100,00 гр formamide |
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0°C273.15 K <br />32 °F <br />491.67 °R <br /> | 27.78 | |||||||||||||
10°C283.15 K <br />50 °F <br />509.67 °R <br /> | 30.91 | |||||||||||||
15°C288.15 K <br />59 °F <br />518.67 °R <br /> | ~32.5 | 0.0265 | ||||||||||||
20°C293.15 K <br />68 °F <br />527.67 °R <br /> | 34.03 | ~0.03 | 19.4 | 0.195 | 9 | |||||||||
25°C298.15 K <br />77 °F <br />536.67 °R <br /> | 36.01 | 0.0288 | 0.54 | 6.7 | 0.073 | 5.18 | ~0.21 | 0.004 | 2.45 | 0.05 | 2.1 | 6.2 | ||
30°C303.15 K <br />86 °F <br />545.67 °R <br /> | 37.47 | ~0.03 | 0.56 | ~0.22 | ||||||||||
40°C313.15 K <br />104 °F <br />563.67 °R <br /> | 40.31 | 0.0325 | 0.60 | ~0.24 | ||||||||||
50°C323.15 K <br />122 °F <br />581.67 °R <br /> | 43.05 | 0.039 | 0.63 | ~0.26 | ||||||||||
60°C333.15 K <br />140 °F <br />599.67 °R <br /> | 45.64 | ~0.04 | 0.67 | 0.285 | ||||||||||
70°C343.15 K <br />158 °F <br />617.67 °R <br /> | 48.33 | ~0.04 | ~0.34 | |||||||||||
80°C353.15 K <br />176 °F <br />635.67 °R <br /> | 50.85 | 0.049 | ~0.40 | |||||||||||
90°C363.15 K <br />194 °F <br />653.67 °R <br /> | 53.82 | 0.457 | ||||||||||||
100°C373.15 K <br />212 °F <br />671.67 °R <br /> | 56.37 |
Gallery
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Growth during 2 monthsPotassium chloride, Aleksandr Chernikh, VKontakteVKontakte
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Mixture of potassium and sodium chloridesPotassium chloride, Inna Mudrik, VKontakteVKontakte
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A mixture of sodium and potassium chlorides in 3:2 ratioPotassium chloride, Andrey Zmitrovich, VKontakteVKontakte
Video
Sources