Monopotassium phosphate

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Monopotassium phosphate

Two unit cells of MKP viewed close to the b axis
Names
IUPAC names
Potassium dihydrogen phosphate[1]
Other names
Potassium phosphate monobasic;
Phosphoric acid, monopotassium salt;
Potassium biphosphate
Identifiers
3D model (
JSmol
)
ChEMBL
ChemSpider
ECHA InfoCard
 100.029.012 Edit this at Wikidata
EC Number
  • 231-913-4
E number E340(i) (antioxidants, ...)
RTECS number
  • TC6615500
UNII
  • InChI=1S/3K.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3 checkY
    Key: LWIHDJKSTIGBAC-UHFFFAOYSA-K checkY
  • InChI=1/3K.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3
    Key: LWIHDJKSTIGBAC-DFZHHIFOAX
  • [K+].OP(O)([O-])=O
Properties
KH
2PO
4
Molar mass 136.086 g/mol
Appearance Colourless crystals or white granular or crystalline powder[2]
Odor Odorless [2]
Density 2.338 g/cm3
Melting point 252.6 °C (486.7 °F; 525.8 K) [4]
Boiling point 400 °C (752 °F; 673 K) , decomposes
22.6 g/100 mL (20 °C)
83.5 g/100 mL (90 °C)
Solubility Slightly soluble in ethanol
Acidity (pKa) 6.86[3]
Basicity (pKb) 11.9
1.4864
Structure
Tetragonal[5]
I42d
a = 0.744 nm, b = 0.744 nm, c = 0.697 nm
Hazards
GHS labelling:
GHS07: Exclamation mark[6]
Warning[6]
H315, H319[6]
P264, P280, P305+P351+P338, P321, P332+P313, P337+P313[6]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
3200 mg/kg (rat, oral)
Safety data sheet (SDS) External MSDS
Related compounds
Other cations
Monoammonium phosphate
Related compounds
 Dipotassium phosphate
Tripotassium phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Monopotassium phosphate (MKP) (also, potassium dihydrogen phosphate, KDP, or monobasic potassium phosphate) is the

buffering agent. The salt often cocrystallizes with the dipotassium salt as well as with phosphoric acid.[7]

ferroelectric
.

Structure

Monopotassium phosphate can exist in several

ferroelectric phase of orthorhombic symmetry, and the transition temperature shifts up to −50 °C (−58 °F) when hydrogen is replaced by deuterium.[8] Heating to 190 °C (374 °F) changes its structure to monoclinic.[9]
When heated further, MKP decomposes, by loss of water, to potassium metaphosphate, KPO
3, at 400 °C (752 °F).

Symmetry Space
group 		№ Pearson
symbol 		a
(nm) 		b
(nm) 		c
(nm) 		Z Density
(g/cm3) 		T (°C, °F, K)
Orthorhombic[8]
 Fdd2 43 oF48 1.0467 1.0533 0.6926 8 2.37 < −150 °C, −238 °F, 123 K
Tetragonal[5]
 I42d 122 tI24 0.744 0.744 0.697 4 2.34 −150 to 190 °C, −238 to 374 °F, 123 to 463 K
Monoclinic[9]
 P21/c 14 mP48 0.733 1.449 0.747 8 190 to 400 °C, 374 to 752 °F, 463 to 673 K

Manufacturing

Monopotassium phosphate is produced by the action of phosphoric acid on potassium carbonate.

Applications

Fertilizer-grade MKP powder contains the equivalent of 52% P
2O
5 and 34% K
2O, and is labeled

NPK 0-52-34. MKP powder is often used as a nutrient source in the greenhouse trade and in hydroponics
.

As a

non-linear optics such as second-harmonic generation
(SHG).

Also, to be noted is KD*P,

neodymium-based lasers
. Regular KDP has absorbances at this wavelength of approximately 4.7–6.3% per cm of thickness while highly deuterated KDP has absorbances of typically less than 0.8% per cm.

Monopotassium phosphate is also used as an ingredient in sports drinks such as Gatorade and Powerade.

In medicine, monopotassium phosphate is used for phosphate substitution in hypophosphatemia.[10]

Gallery

References

  1. ^ "Potassium dihydrogen phosphate".
  2. ^ a b "Commission Regulation (EU) No 231/2012 of 9 March 2012 laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 of the European Parliament and of the Council Text with EEA relevance". EUR-Lex. E 340 (i) MONOPOTASSIUM PHOSPHATE. Retrieved 19 January 2023.{{cite web}}: CS1 maint: location (link)
  3. ^ Mathews, Christopher K., K. E. Van Holde, Ean R. Appling, and Spencer J. Anthony-Cahill. Biochemistry. Redwood City, CA: Benjamin/Cummings Pub., 1990. Print.
  4. ^ King, Harold S. J. Am. Chem. Soc. 1927, 49, 6, 1511–1512 https://doi.org/10.1021/ja01405a018
  5. ^
    doi:10.1143/JPSJ.56.577
    .
  6. ^ a b c d "Potassium Dihydrogen Phosphate". American Elements. Retrieved October 30, 2018.
  7. ISBN 978-3527306732
    .
  8. ^
    doi:10.1002/pssa.2211170234
    .
  9. ^
    doi:10.1143/JPSJ.39.843
    .
  10. PMID 16194637
    .

External links

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