Potassium chloride

Potassium chloride
Names:	potassium chloride muriate of potash MOP Е508 food additive PubChem: 4873 CAS: 7447-40-7 CAS: 14336-88-0 InChI Key: WCUXLLCKKVVCTQ-UHFFFAOYSA-M
Formula:	KCl
SMILES:	[Cl-].[K+]
Molar mass:	74.551 g/mol
Density:	1.988 g/cm3
Crystal system:	cubic a=6.29294 Å 6.2929 Å 0.6293 nm , b=6.29294 Å 6.2929 Å 0.6293 nm , c=6.29294 Å 6.2929 Å 0.6293 nm α=90° 90°   , β=90° 90°   , γ=90° 90°
Shapes:	https://media.crystalls.info/w/uploads/media/Cube.json Cube https://media.crystalls.info/w/uploads/media/Tetragonal_prism.json Tetragonal prism https://media.crystalls.info/w/uploads/media/Tetragonal_flat_prism.json Tetragonal flat prism https://media.crystalls.info/w/uploads/media/Tetragonal_pedion.json Tetragonal pedion https://media.crystalls.info/w/uploads/media/Needle.json Needle
Color:	colorless
Melting point:	776 °C 1,049.15 K 1,428.8 °F 1,888.47 °R
Boiling point:	1420 °C 1,693.15 K 2,588 °F 3,047.67 °R
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

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:

HCl + KOH = KCl + H₂O

2HCl + K₂CO₃ = 2KCl + H₂O + CO₂↑

For preparation of 100.00g of potassium chloride а 75.26g of potassium hydroxide or 92.69g of carbonate and 128.70g of 38%

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

TableGraph

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
0°C 273.15 K 32 °F 491.67 °R	27.78 27.78 g/100g 21.74 %
10°C 283.15 K 50 °F 509.67 °R	30.91 30.91 g/100g 23.612 %
15°C 288.15 K 59 °F 518.67 °R	~32.5 32.5 g/100g 24.528 %	0.0265 0.0265 g/100g 0.0265 %
20°C 293.15 K 68 °F 527.67 °R	34.03 34.03 g/100g 25.39 %	~0.03 0.03 g/100g 0.03 %					19.4 19.4 g/100g 16.248 %	0.195 0.195 g/100g 0.195 %		9 9 g/100g 8.257 %
25°C 298.15 K 77 °F 536.67 °R	36.01 36.01 g/100g 26.476 %	0.0288 0.0288 g/100g 0.0288 %	0.54 0.54 g/100g 0.537 %	6.7 6.7 g/100g 6.279 %	0.073 0.073 g/100g 0.0729 %	5.18 5.18 g/100g 4.925 %		~0.21 0.21 g/100g 0.21 %	0.004 0.004 g/100g 0.004 %		2.45 2.45 g/100g 2.391 %	0.05 0.05 g/100g 0.05 %	2.1 2.1 g/100g 2.057 %	6.2 6.2 g/100g 5.838 %
30°C 303.15 K 86 °F 545.67 °R	37.47 37.47 g/100g 27.257 %	~0.03 0.03 g/100g 0.03 %	0.56 0.56 g/100g 0.557 %					~0.22 0.22 g/100g 0.22 %
40°C 313.15 K 104 °F 563.67 °R	40.31 40.31 g/100g 28.729 %	0.0325 0.0325 g/100g 0.0325 %	0.60 0.6 g/100g 0.596 %					~0.24 0.24 g/100g 0.239 %
50°C 323.15 K 122 °F 581.67 °R	43.05 43.05 g/100g 30.094 %	0.039 0.039 g/100g 0.039 %	0.63 0.63 g/100g 0.626 %					~0.26 0.26 g/100g 0.259 %
60°C 333.15 K 140 °F 599.67 °R	45.64 45.64 g/100g 31.338 %	~0.04 0.04 g/100g 0.04 %	0.67 0.67 g/100g 0.666 %					0.285 0.285 g/100g 0.284 %
70°C 343.15 K 158 °F 617.67 °R	48.33 48.33 g/100g 32.583 %	~0.04 0.04 g/100g 0.04 %						~0.34 0.34 g/100g 0.339 %
80°C 353.15 K 176 °F 635.67 °R	50.85 50.85 g/100g 33.709 %	0.049 0.049 g/100g 0.049 %						~0.40 0.4 g/100g 0.398 %
90°C 363.15 K 194 °F 653.67 °R	53.82 53.82 g/100g 34.989 %							0.457 0.457 g/100g 0.455 %
100°C 373.15 K 212 °F 671.67 °R	56.37 56.37 g/100g 36.049 %

Slightly soluble in pyridine. Insoluble in acetone, acetonitrile and amyl alcohol.

Gallery

• 

  Potassium chlorideVladimir Romaniv, VKontakteVladimir RomanivVKontakte

• 

  Potassium chlorideInna Mudrik, VKontakteInna MudrikVKontakte

• 

  Potassium chlorideMaxim Martinov, VKontakteMaxim MartinovVKontakte

• 

  Potassium chlorideMaxim Martinov, VKontakteMaxim MartinovVKontakte

• 

  Potassium chlorideVladimir Romaniv, VKontakteVladimir RomanivVKontakte

• 

  Potassium chlorideVladimir Romaniv, VKontakteVladimir RomanivVKontakte

• 

  Potassium chlorideVladimir Romaniv, VKontakteVladimir RomanivVKontakte

• 

  Growth during 2 monthsPotassium chloride, Aleksandr Chernikh, VKontakteAleksandr ChernikhVKontakte

• 

  Mixture of potassium and sodium chloridesPotassium chloride, Inna Mudrik, VKontakteInna MudrikVKontakte

• 

  A mixture of sodium and potassium chlorides in 3:2 ratioPotassium chloride, Andrey Zmitrovich, VKontakteAndrey ZmitrovichVKontakte

Sources

• R.A.Kiper Properties of compounds. Handbook
• R.Wyckoff, Rocksalt crystal structure
• S.Pinho, Solubility of NaCl, NaBr, and KCl in Water, Methanol, Ethanol, and Their Mixed Solvents
• Etacude.com reference

Navigation

Potassium compounds
Salts	Potassium bromate (KBrO3) • Potassium bromide (KBr) • Potassium chlorate (KClO3) • Potassium chloride (KCl) • Potassium chromate (K2CrO4) • Potassium dihydrophosphate (KH2PO4) • Potassium dichromate (K2Cr2O7) • Potassium iodide (KI) • Potassium hydrofluoride (KHF2) • Potassium hydrophosphate (K2HPO4) • Potassium hydrophthalate (KC8H6O4) • Potassium metavanadate (KVO3) • Potassium nitrate (KNO3) • Potassium sulfate (K2SO4) • Potassium thiocyanate (KNCS)
Double salts	Aluminum-potassium sulfate (KAl(SO4)2) • Antimony(III)-potassium tartrate (K2Sb2(C4H2O6)2) • Chromium(III)-potassium sulfate (KCr(SO4)2) • Cobalt(II)-potassium sulfate (K2Co(SO4)2) • Copper(II)-potassium sulfate (K2Cu(SO4)2) • Indium(III)-potassium sulfate (KIn(SO4)2) • Iron(II)-potassium sulfate (K2Fe(SO4)2) • Iron(III)-potassium sulfate (KFe(SO4)2) • Lithium-potassium sulfate (KLiSO4) • Magnesium-potassium sulfate (K2Mg(SO4)2) • Magnesium-potassium sulfate-chromate (K2CrO4 · MgSO4) • Manganese(II)-potassium sulfate (K2Mn(SO4)2) • Nickel-potassium sulfate (K2Ni(SO4)2) • Potassium-sodium tartrate (KNaC4H4O6) • Vanadium(III)-ammonium sulfate (NH4V(SO4)2)
Complexes	Potassium dioxalatocuprate(II) (K2[Cu(C2O4)2]) • Potassium hexanitrocobaltate(III) (K3[Co(NO2)6]) • Potassium hexachlororhodiate(III) (K3[RhCl6]) • Potassium hexacyanocobaltate(III) (K3[Co(CN)6]) • Potassium hexacyanoferrate(II) (K4[Fe(CN)6]) • Tripotassium-sodium hexacyanoferrate(II) (K3Na[Fe(CN)6]) • Potassium hexacyanoferrate(III) (K3[Fe(CN)6]) • Potassium hexacyanochromate(III) (K3[Co(CN)6]) • Potassium tetraiodobismuthate (К[BiI4]) • Potassium tetraiodomercurate(II) (K2[HgI4]) • Potassium trioxalatoaluminate (K3[Al(C2O4)3]) • Potassium trioxalatocobaltate(III) (K3[Co(C2O4)3]) Potassium trioxalatoferrate(III) (K3[Fe(C2O4)3]) • Potassium-sodium trioxalatoferrate(III) (K5Na[Fe(C2O4)3]2) • Dipotassium-sodium trioxalatoferrate(III) (K2Na[Fe(C2O4)3]) • Potassium trioxalatochromate(III) (K3[Cr(C2O4)3])