Citric acid

Citric acid ;
Names:	2-oxypropane-1,2,3-tricarboxylic acid; 2-hydroxypropane-1,2,3-tricarboxylic acid; Е330 food additive;
Formula:	C3H5O(COOH)3 (anhydrous); C3H5O(COOH)3 · H2O (monohydrate);
Molar mass:	192.123 g/mol (anhydrous); 210.137 g/mol (monohydrate);
Density:	1.665 g/cm3 (anhydrous); 1.542 g/cm3 (monohydrate);
Crystal system:	monoclinic (anhydrous); a=12.817 Å, b=5.628 Å, c=11.465 Åα=90°, β=111.22°, γ=90°; orthorhombic (monohydrate); α=90°, β=90°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/0/0e/Truncated_rhombic_bipyramid.json Truncated rhombic bipyramid https://en.crystalls.info/w/uploads/media/f/fa/Truncated_rhombic_pyramid.json Truncated rhombic pyramid Template:Rhombohedron;
Color:	colorless;
Melting point:	153.5 °C426.65 K <br />308.3 °F <br />767.97 °R <br /> (anhydrous);
Decomposition point:	175 °C448.15 K <br />347 °F <br />806.67 °R <br /> (anhydrous);
Refractive index:	1.46 (anhydrous); 1.498 (monohydrate);
Stability:	slightly erodes (monohydrate); hygroscopic (anhydrous);
Hardness:	fragile;
Toxicity:	non-toxic; LD50=3000mg/kg

Description

Organic compound, tribasic carboxylic acid. From water solutions crystallizes as monohydrate.

Where to buy

Can be bought in grocery store (as "citric acid").

Precursors

Reaction between sodium citrate, calcium chloride or nitrate and sulfuric acid

Chemical equation:

2Na₃C₃H₅O(COO)₃ + CaCl₂ = Ca₃(C₃H₅O(COO)₃)₂↓ + 2NaCl

2Na₃C₃H₅O(COO)₃ + Ca(NO₃)₂ = Ca₃(C₃H₅O(COO)₃)₂↓ + 2NaNO₃

Ca₃(C₃H₅O(COO)₃)₂ + 3H₂SO₄ = 2C₃H₅O(COOH)₃ + 3CaSO₄↓

For preparation of 100.00g of citric acid

monohydratemonohydrate
anhydrous

а 104.25g of calcium chloride

hexahydratehexahydrate
anhydrous

or 112.38g of calcium nitrate

tetrahydratetetrahydrate
anhydrous

or 189.21g of 37%37% sulfuric acid is required.

Add to the flask with sodium citrate solution small parts of calcium compounds solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and wash it from soluble impurities few times.Add to the flask with calcium citrate solution small parts of sulfuric acid solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and discard, then filter the solution carefully.

Influence of temperature

If you use hot water to dissolve compound, it formes a syrup which doesn´t crystallize even after freezing.

Storage conditions

Keep in its original form or under several layers of varnish at average humidity and room temperature. Do not keep crystals near heaters.

Solubility

TableGraph

Temperature	g/`100,00` g water		g/`100,00` g ethanol		g/`100,00` g methanol	g/`100,00` g diethyl ether		g/`100,00` g ethyl acetate	g/`100,00` g formic acid 95%	g/`100,00` g propanol	g/`100,00` g amyl alcohol	g/`100,00` g dioxane
Temperature	(anhydrous)	(monohydrate)	(anhydrous)	(monohydrate)	(monohydrate)	(anhydrous)	(monohydrate)	(monohydrate)	(anhydrous)	(monohydrate)	(monohydrate)	(anhydrous)
0°C273.15 K <br />32 °F <br />491.67 °R <br />	`32.66`
10°C283.15 K <br />50 °F <br />509.67 °R <br />	`35.02`	`117.4`
15°C288.15 K <br />59 °F <br />518.67 °R <br />
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`59.2`	`145.1`			`200`				`12.25`	`62.6`
25°C298.15 K <br />77 °F <br />536.67 °R <br />			`62`	`99.2`		`1.05`	`2.25`	`5.6`			`18.25`	`35.9`
30°C303.15 K <br />86 °F <br />545.67 °R <br />		`180.1`
40°C313.15 K <br />104 °F <br />563.67 °R <br />		`218.5`
50°C323.15 K <br />122 °F <br />581.67 °R <br />		`243.6`
60°C333.15 K <br />140 °F <br />599.67 °R <br />		`277.4`
70°C343.15 K <br />158 °F <br />617.67 °R <br />		`320.2`
80°C353.15 K <br />176 °F <br />635.67 °R <br />		`371.7`
90°C363.15 K <br />194 °F <br />653.67 °R <br />		`437.6`
100°C373.15 K <br />212 °F <br />671.67 °R <br />		`525.0`

Insoluble in toluene, benzene and carbon disulfide.

Gallery

Grown during 26 daysCitric acid, Oleg Grigor`ev, VKontakteOleg Grigor`evVKontakte
Grown during 26 daysCitric acid, Oleg Grigor`ev, VKontakteOleg Grigor`evVKontakte
Grown during 2 monthsCitric acid, Maxim Martinov, VKontakteMaxim MartinovVKontakte
Grown during 2 monthsCitric acid, Maxim Martinov, VKontakteMaxim MartinovVKontakte
Grown during 2 monthsCitric acid, Martinov Maxim, VKontakteMartinov MaximVKontakte
Grown during 2 monthsCitric acid, Martinov Maxim, VKontakteMartinov MaximVKontakte
Citric acidAnton Pershin, VKontakteAnton PershinVKontakte
Citric acidAnton Pershin, VKontakteAnton PershinVKontakte
Growing from distilled waterCitric acid, Klim Kolinenko, VKontakteKlim KolinenkoVKontakte
Citric acidRuslan Krasnonis, Chemistry chemists periodicalRuslan KrasnonisChemistry chemists periodical
Citric acidRuslan Krasnonis, Chemistry chemists periodicalRuslan KrasnonisChemistry chemists periodical
Citric acidViktoriya Shipova, VKontakteViktoriya ShipovaVKontakte

Video

Sources

Citrates
Ammonium citrate ((NH₄)₃C₃H₅O(COO)₃) • Citric acid (C₃H₅O(COOH)₃) • Iron(II) citrate (FeHC₃H₅O(COO)₃) • Lead(II) citrate (Pb₃(C₃H₅O(COO)₃)₂) • Sodium citrate (Na₃C₃H₅O(COO)₃) • Urea citrate (CO(NH₂)₂ · C₃H₅O(COOH)₃)

Acids

Inorganic

Boric (H₃BO₃) • Disulfozirconium (H₂ZrO(SO₄)₂) • Tetrachlorauric (H[AuCl₄])

Organic

4-aminobenzoic (H₂NC₆H₄COOH) • Acetylsalicylic (C₉H₈O₄) • Ascorbic (C₆H₈O₆) • Benzoic (C₆H₅СООН) • Citric (C₃H₅O(COOH)₃) • Cyclamic (C₆H₁₃NO₃S) • Glutamic (C₅H₉NO₄) • Glycine (NH₂CH₂COOH) • Oxalic (HOOCСООН) • Phenol (C₆H₅OH) • Phthalic acid (C₈H₆O₄) • Saccarin (C₇H₅NO₃S) • Salycilic (С6Н4(OH)CООН) • Sulfamic (H₂NSO₃H) • Succinic (НООССН2СН2СООН) • Tartaric (C₄H₆O₆) • Trichloroisocyanuric (C₃Cl₃N₃O₃) • Vanillic (C₈H₈O₄)

Citric acid
Names:	2-oxypropane-1,2,3-tricarboxylic acid 2-hydroxypropane-1,2,3-tricarboxylic acid Е330 food additive
Formula:	C₃H₅O(COOH)₃ (anhydrous) C₃H₅O(COOH)₃ · H₂O (monohydrate)
Molar mass:	192.123 g/mol (anhydrous) 210.137 g/mol (monohydrate)
Density:	1.665 g/cm³ (anhydrous) 1.542 g/cm³ (monohydrate)
Crystal system:	monoclinic (anhydrous) a=12.817 Å, b=5.628 Å, c=11.465 Åα=90°, β=111.22°, γ=90° orthorhombic (monohydrate) α=90°, β=90°, γ=90°
Shapes:	Truncated rhombic bipyramid Truncated rhombic pyramid Template:Rhombohedron
Color:	colorless
Melting point:	153.5 °C426.65 K <br />308.3 °F <br />767.97 °R <br /> (anhydrous)
Decomposition point:	175 °C448.15 K <br />347 °F <br />806.67 °R <br /> (anhydrous)
Refractive index:	1.46 (anhydrous) 1.498 (monohydrate)
Stability:	slightly erodes (monohydrate) hygroscopic (anhydrous)
Hardness:	fragile
Toxicity:	non-toxic LD₅₀=3000mg/kg