Potassium hydrogen phthalate

Potassium hydrogen phthalate
Names:	potassium hydrogen phthalate potassium acid phthalate potassium acid orho-phthalate potassium diphthalate KHP KAP
Formula:	C8H6O4K
Molar mass:	205.230 g/mol
Density:	1.636 g/cm3
Crystal system:	orthorhombic a=6.46 Å, b=9.6 Å, c=18.25 Åα=90°, β=90°, γ=90°
Shapes:	https://en.crystalls.info/w/uploads/media/7/7f/Truncated_hexagonal_bipyramid.json Truncated hexagonal bipyramid https://en.crystalls.info/w/uploads/media/9/9c/Truncated_hexagonal_pyramid.json Truncated hexagonal pyramid https://en.crystalls.info/w/uploads/media/0/0e/Truncated_rhombic_bipyramid.json Truncated rhombic bipyramid
Color:	colorless
Decomposition point:	295 °C568.15 K <br />563 °F <br />1,022.67 °R <br />
Optical properties:	birefringence
Stability:	stable

Description

Inorganic compound, acid salt of alkaline metal potassium and dibasic phthaleic acid. Doesn't form water hydrates.

Influence of impurities

Small addition (1%) of urea improves crystal transparency. Same effect can be achieved by adding glycine, up to 10%

Solubility

TableGraph

Temperature	g/100,00 g water
20°C293.15 K <br />68 °F <br />527.67 °R <br />	8

Slightly soluble in ethanol.

Gallery

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  Grown in 3 weeksPotassium hydrogen phthalate, Eugene Dudko, VKontakteEugene DudkoVKontakte

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  Addition of rhodamine-110 dyePotassium hydrogen phthalate, Terry Bartlett, Flickr albumTerry BartlettFlickr album

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  Addition of rhodamine-110 dyePotassium hydrogen phthalate, Terry Bartlett, Flickr albumTerry BartlettFlickr album

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  File:s.popov.potassium.hydrophtalate.1.jpg

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  File:s.popov.potassium.hydrophtalate.2.jpg

Video

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Sources

• Y. Okaya, The crystal structure of potassium acid phthalate
• P. Murugakoothan, R M. Kumar, P. M. Ushasree, R. Jayavel, R. Dhanasekaran, P Ramasamy, Habit modification of potassium acid phthalate (KAP) single crystals by impurities
• N. Sivakumar, J. Venkatamuthukumar, A. Alsalme, Growth, structural, spectroscopic, optical, and mechanical studies of potassium hydrogen phthalate single crystals with glycine as additive

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 hydrogen phthalate (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) • Zinc-potassium sulfate (K2Zn(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])