What is the standard enthalpy of formation?

It is the enthalpy change when one mole of a substance forms from its elements in their reference states at 298.15 K and 1 bar, written ΔHf° and given in kJ/mol. Negative values mean heat is released on formation.

Why is the enthalpy of formation of an element zero?

Forming an element from itself involves no change, so ΔHf° is defined as zero for the reference state at 298.15 K and 1 bar, which is usually the most stable form: O₂(g), H₂(g), N₂(g), graphite, Br₂(l), white phosphorus and the metals. Other forms are not zero, for example diamond and ozone, which is why the table lists them.

How do I calculate the enthalpy of a reaction from this table?

Balance the equation, look up ΔHf° for each species in the right state, and compute ΔH°rxn = ΣnΔHf°(products) − ΣnΔHf°(reactants). The reaction calculator on this page does the sums, checks the element balance, and also returns ΔG° and ΔS°.

Why does water appear twice in the table?

ΔHf° depends on the state. Liquid water and water vapor differ by the heat of vaporization at 298 K, about 44 kJ/mol. Pick the state that matches your equation, because mixing them changes ΔH°rxn.

What is the difference between ΔHf° and ΔGf°?

ΔHf° is the heat of formation. ΔGf° is the Gibbs energy of formation, which includes the entropy change and tells you whether forming the compound from its elements is spontaneous at 298 K. They are related by ΔG = ΔH − TΔS.

Why do different tables give slightly different values?

Tables draw on different measurements, evaluation dates and standard pressures (1 atm or 1 bar). Differences are usually under a kilojoule per mole but can be larger for older or hard-to-measure species. This page uses the NBS evaluation for almost every row, so those values stay consistent with each other, and marks the rows that come from the NIST WebBook.

Chemistry Reference

Standard Enthalpy of Formation Table ΔHf°, ΔGf°, S° & Reaction Calculator

Searchable enthalpy of formation table: 177 substances with ΔHf°, ΔGf° and S° at 298.15 K, plus a reaction enthalpy calculator. Printable.

177 substances from the NBS tables and NIST WebBookSearch by name or formula: methane, CO2, NaClReaction calculator: ΔH°, ΔG°, ΔS°, element balance checkPNG, SVG and print, no sign-up

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Showing 177 of 177 substances

Substance	Formula	State	ΔH_f° kJ/mol	ΔG_f° kJ/mol	S° J/(mol·K)
Aluminum	Al	solid	0	0	28.33
Bromine	Br₂	liquid	0	0	152.231
BromineGas phase, not the reference state of bromine	Br₂	gas	30.907	3.110	245.463
Bromine atomGaseous atom, used for atomization enthalpies	Br	gas	111.884	82.396	175.022
Calcium (α)	Ca	solid	0	0	41.42
Carbon (graphite)Reference state of carbon	C	solid	0	0	5.740
Carbon (diamond)Not the reference state, so ΔHf° is not zero	C	solid	1.895	2.900	2.377
Carbon atomGaseous atom, used for atomization enthalpies	C	gas	716.682	671.257	158.096
Chlorine	Cl₂	gas	0	0	223.066
Chlorine atomGaseous atom, used for atomization enthalpies	Cl	gas	121.679	105.680	165.198
Copper	Cu	solid	0	0	33.150
Fluorine	F₂	gas	0	0	202.78
Fluorine atomGaseous atom, used for atomization enthalpies	F	gas	78.99	61.91	158.754
Hydrogen	H₂	gas	0	0	130.684
Hydrogen atomGaseous atom, used for atomization enthalpies	H	gas	217.965	203.247	114.713
Iodine	I₂	solid	0	0	116.135
IodineGas phase, not the reference state of iodine	I₂	gas	62.438	19.327	260.69
Iron	Fe	solid	0	0	27.28
Lead	Pb	solid	0	0	64.81
Lithium	Li	solid	0	0	29.12
Magnesium	Mg	solid	0	0	32.68
Manganese	Mn	solid	0	0	32.01
Mercury	Hg	liquid	0	0	76.02
Nitrogen	N₂	gas	0	0	191.61
Nitrogen atomGaseous atom, used for atomization enthalpies	N	gas	472.704	455.563	153.298
Oxygen	O₂	gas	0	0	205.138
Oxygen atomGaseous atom, used for atomization enthalpies	O	gas	249.170	231.731	161.055
OzoneAllotrope of O2, not the reference state	O₃	gas	142.7	163.2	238.93
Phosphorus (white)Reference state of phosphorus (white); formula written as P	P	solid	0	0	41.09
Potassium	K	solid	0	0	64.18
Silicon	Si	solid	0	0	18.83
Silver	Ag	solid	0	0	42.55
Sodium	Na	solid	0	0	51.21
Sulfur (rhombic)	S	solid	0	0	31.80
Tin (white)	Sn	solid	0	0	51.55
Zinc	Zn	solid	0	0	41.63
Aluminum oxide (corundum)	Al₂O₃	solid	−1675.7	−1582.3	50.92
Calcium oxide	CaO	solid	−635.09	−604.03	39.75
Carbon dioxide	CO₂	gas	−393.509	−394.359	213.74
Carbon monoxide	CO	gas	−110.525	−137.168	197.674
Copper(I) oxideNIST WebBook lists −170.71 kJ/mol from a different source	Cu₂O	solid	−168.6	−146.0	93.14
Copper(II) oxideNIST WebBook lists −156.06 kJ/mol from a different source	CuO	solid	−157.3	−129.7	42.63
Dinitrogen monoxide	N₂O	gas	82.05	104.20	219.85
Dinitrogen tetroxide	N₂O₄	gas	9.16	97.89	304.29
Hydrogen peroxide	H₂O₂	liquid	−187.78	−120.35	109.6
Iron(II,III) oxide (magnetite)	Fe₃O₄	solid	−1118.4	−1015.4	146.4
Iron(III) oxide (hematite)	Fe₂O₃	solid	−824.2	−742.2	87.40
Lead(II) oxide (red)	PbO	solid	−218.99	−188.93	66.5
Lead(II) oxide (yellow)	PbO	solid	−217.32	−187.89	68.70
Lithium oxide	Li₂O	solid	−597.94	−561.18	37.57
Magnesium oxide (periclase)	MgO	solid	−601.70	−569.43	26.94
Manganese(IV) oxide	MnO₂	solid	−520.03	−465.14	53.05
Mercury(II) oxide (red)	HgO	solid	−90.83	−58.539	70.29
Nitrogen dioxide	NO₂	gas	33.18	51.31	240.06
Nitrogen monoxide	NO	gas	90.25	86.55	210.761
Silicon dioxide (quartz)	SiO₂	solid	−910.94	−856.64	41.84
Silver oxide	Ag₂O	solid	−31.05	−11.20	121.3
Sodium oxideNIST WebBook lists −417.98 kJ/mol	Na₂O	solid	−414.22	−375.46	75.06
Sulfur dioxide	SO₂	gas	−296.830	−300.194	248.22
Sulfur trioxide	SO₃	gas	−395.72	−371.06	256.76
Water	H₂O	liquid	−285.830	−237.129	69.91
Water vapor	H₂O	gas	−241.818	−228.572	188.825
Zinc oxideNIST WebBook lists −350.46 kJ/mol from a different source	ZnO	solid	−348.28	−318.30	43.64
Ammonia	NH₃	gas	−46.11	−16.45	192.45
Hydrazine	N₂H₄	liquid	50.63	149.34	121.21
Hydrogen bromide	HBr	gas	−36.40	−53.45	198.695
Hydrogen chloride	HCl	gas	−92.307	−95.299	186.908
Hydrogen cyanide	HCN	gas	135.1	124.7	201.78
Hydrogen fluorideNewer evaluations give about −273.3 kJ/mol (NIST WebBook)	HF	gas	−271.1	−273.2	173.779
Hydrogen iodide	HI	gas	26.48	1.70	206.594
Hydrogen sulfide	H₂S	gas	−20.63	−33.56	205.79
Nitric acid	HNO₃	liquid	−174.10	−80.71	155.60
Phosphine	PH₃	gas	5.4	13.4	210.23
Silane	SiH₄	gas	34.3	56.9	204.62
Sulfuric acid	H₂SO₄	liquid	−813.989	−690.003	156.904
Ammonium chloride	NH₄Cl	solid	−314.43	−202.87	94.6
Ammonium nitrate	NH₄NO₃	solid	−365.56	−183.87	151.08
Ammonium sulfate	(NH₄)₂SO₄	solid	−1180.85	−901.67	220.1
Calcium carbonate (calcite)	CaCO₃	solid	−1206.92	−1128.79	92.9
Calcium carbonate (aragonite)	CaCO₃	solid	−1207.13	−1127.75	88.7
Calcium chloride	CaCl₂	solid	−795.8	−748.1	104.6
Calcium fluorideNIST WebBook lists −1225.91 kJ/mol	CaF₂	solid	−1219.6	−1167.3	68.87
Calcium hydroxide	Ca(OH)₂	solid	−986.09	−898.49	83.39
Calcium sulfate (anhydrite)	CaSO₄	solid	−1434.11	−1321.79	106.7
Copper(II) sulfate	CuSO₄	solid	−771.36	−661.8	109
Copper(II) sulfide	CuS	solid	−53.1	−53.6	66.5
Iron disulfide (pyrite)	FeS₂	solid	−178.2	−166.9	52.93
Lead(II) sulfate	PbSO₄	solid	−919.94	−813.14	148.57
Lead(II) sulfideNIST WebBook lists −98.32 kJ/mol from a different source	PbS	solid	−100.4	−98.7	91.2
Lithium chloride	LiCl	solid	−408.61	−384.37	59.33
Magnesium carbonate (magnesite)NIST WebBook lists −1111.69 kJ/mol	MgCO₃	solid	−1095.8	−1012.1	65.7
Magnesium chloride	MgCl₂	solid	−641.32	−591.79	89.62
Magnesium hydroxide	Mg(OH)₂	solid	−924.54	−833.51	63.18
Phosphorus pentachloride	PCl₅	gas	−374.9	−305.0	364.58
Phosphorus trichloride	PCl₃	liquid	−319.7	−272.3	217.1
Phosphorus trichlorideNIST WebBook lists −288.7 kJ/mol	PCl₃	gas	−287.0	−267.8	311.78
Potassium bromide	KBr	solid	−393.798	−380.66	95.90
Potassium chlorate	KClO₃	solid	−397.73	−296.25	143.1
Potassium chloride	KCl	solid	−436.747	−409.14	82.59
Potassium fluoride	KF	solid	−567.27	−537.75	66.57
Potassium hydroxide	KOH	solid	−424.764	−379.08	78.9
Potassium iodideNBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°	KI	solid	−327.900	−324.892	106.32
Potassium nitrate	KNO₃	solid	−494.63	−394.86	133.05
Potassium sulfateNBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°	K₂SO₄	solid	−1437.79	−1321.37	175.56
Silicon tetrachloride	SiCl₄	liquid	−687.0	−619.84	239.7
Silicon tetrafluoride	SiF₄	gas	−1614.94	−1572.65	282.49
Silver bromide	AgBr	solid	−100.37	−96.90	107.1
Silver chloride	AgCl	solid	−127.068	−109.789	96.2
Silver iodide	AgI	solid	−61.84	−66.19	115.5
Silver nitrate	AgNO₃	solid	−124.39	−33.41	140.92
Sodium bicarbonateNBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°	NaHCO₃	solid	−950.81	−851.0	101.7
Sodium bromide	NaBr	solid	−361.062	−348.983	86.82
Sodium carbonateNBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°	Na₂CO₃	solid	−1130.68	−1044.44	134.98
Sodium chloride	NaCl	solid	−411.153	−384.138	72.13
Sodium fluorideNIST WebBook lists −575.38 kJ/mol	NaF	solid	−573.647	−543.494	51.46
Sodium hydroxide	NaOH	solid	−425.609	−379.494	64.455
Sodium iodideNBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°	NaI	solid	−287.78	−286.06	98.53
Sodium nitrate	NaNO₃	solid	−467.85	−367.00	116.52
Sodium nitrite	NaNO₂	solid	−358.65	−284.55	103.8
Sodium sulfateNBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°	Na₂SO₄	solid	−1387.08	−1270.16	149.58
Zinc sulfateNIST WebBook lists −980.14 kJ/mol from a different source	ZnSO₄	solid	−982.8	−871.5	110.5
Zinc sulfide (sphalerite)	ZnS	solid	−205.98	−201.29	57.7
BenzeneΔHf° and S° from NIST WebBook; ΔGf° computed from them; ΔHf° is the WebBook review value, consistent with the two combustion measurements	C₆H₆	liquid	49.0	124.5	173.26
Ethane	C₂H₆	gas	−84.68	−32.82	229.60
Ethene (ethylene)	C₂H₄	gas	52.26	68.15	219.56
Ethyne (acetylene)	C₂H₂	gas	226.73	209.20	200.94
HexaneΔHf° and S° from NIST WebBook; ΔGf° computed from them	C₆H₁₄	liquid	−198.7	−4.0	296.06
HexaneΔHf° and S° from NIST WebBook; ΔGf° computed from them	C₆H₁₄	gas	−167.1	0	388.82
Methane	CH₄	gas	−74.81	−50.72	186.264
OctaneΔHf° and S° from NIST WebBook; ΔGf° computed from them	C₈H₁₈	liquid	−250.3	6.4	361.20
OctaneΔHf° and S° from NIST WebBook; ΔGf° computed from them	C₈H₁₈	gas	−208.7	16.4	467.06
PentaneΔHf° and S° from NIST WebBook; ΔGf° computed from them	C₅H₁₂	liquid	−173.5	−9.7	263.47
PentaneΔHf° and S° from NIST WebBook; ΔGf° computed from them	C₅H₁₂	gas	−146.8	−8.2	347.82
TolueneΔHf° and S° from NIST WebBook; ΔGf° computed from them; ΔHf° is the WebBook review value	C₇H₈	liquid	12.0	114.0	220.96
1-PropanolΔHf° and S° from NIST WebBook; ΔGf° computed from them; WebBook lists S° of 192.8 and 214.2 J/(mol·K) from different studies, the first listed is used	C₃H₇OH	liquid	−302.54	−168.5	192.8
AcetaldehydeNIST WebBook lists −170.7 kJ/mol	CH₃CHO	gas	−166.19	−128.86	250.3
Acetic acid	CH₃COOH	liquid	−484.5	−389.9	159.8
AcetoneΔHf° and S° from NIST WebBook; ΔGf° computed from them; WebBook lists several S° values between 200.0 and 217.6, the first listed is used	C₃H₆O	liquid	−249.4	−156.5	200.4
Carbon disulfide	CS₂	liquid	89.70	65.27	151.34
Carbon tetrachlorideNewer evaluations give about −128 kJ/mol (NIST WebBook)	CCl₄	liquid	−135.44	−65.21	216.40
Chloroform	CHCl₃	liquid	−134.47	−73.66	201.7
Chloromethane	CH₃Cl	gas	−80.83	−57.37	234.58
EthanolNIST WebBook lists −276.0 kJ/mol	C₂H₅OH	liquid	−277.69	−174.78	160.7
Ethanol	C₂H₅OH	gas	−235.10	−168.49	282.70
Ethylene glycol	(CH₂OH)₂	liquid	−454.80	−323.08	166.9
Formaldehyde	HCHO	gas	−108.57	−102.53	218.77
Formic acid	HCOOH	liquid	−424.72	−361.35	128.95
Methanol	CH₃OH	liquid	−238.66	−166.27	126.8
MethanolNIST WebBook lists −205.0 kJ/mol	CH₃OH	gas	−200.66	−161.96	239.81
Methylamine	CH₃NH₂	gas	−22.97	32.16	243.41
SucroseΔHf° and S° from NIST WebBook; ΔGf° computed from them; ΔHf° is a single combustion measurement (1939)	C₁₂H₂₂O₁₁	solid	−2221.2	−1552.7	392.4
Urea	CO(NH₂)₂	solid	−333.51	−197.33	104.60
Acetate ion	CH₃COO⁻	aqueous	−486.01	−369.31	86.6
Aluminum ionNBS lists ΔHf° and ΔGf° to the nearest kJ/mol	Al³⁺	aqueous	−531	−485	−321.7
Ammonium ion	NH₄⁺	aqueous	−132.51	−79.31	113.4
Bromide ion	Br⁻	aqueous	−121.55	−103.96	82.4
Calcium ion	Ca²⁺	aqueous	−542.83	−553.58	−53.1
Carbonate ion	CO₃²⁻	aqueous	−677.14	−527.81	−56.9
Chloride ion	Cl⁻	aqueous	−167.159	−131.228	56.5
Copper(II) ion	Cu²⁺	aqueous	64.77	65.49	−99.6
Fluoride ion	F⁻	aqueous	−332.63	−278.79	−13.8
Hydrogen carbonate ion	HCO₃⁻	aqueous	−691.99	−586.77	91.2
Hydrogen ionDefined as zero for every property (1 mol/kg standard state)	H⁺	aqueous	0	0	0
Hydrogen sulfate ion	HSO₄⁻	aqueous	−887.34	−755.91	131.8
Hydroxide ion	OH⁻	aqueous	−229.994	−157.244	−10.75
Iodide ion	I⁻	aqueous	−55.19	−51.57	111.3
Iron(II) ion	Fe²⁺	aqueous	−89.1	−78.90	−137.7
Iron(III) ion	Fe³⁺	aqueous	−48.5	−4.7	−315.9
Lithium ion	Li⁺	aqueous	−278.49	−293.31	13.4
Magnesium ion	Mg²⁺	aqueous	−466.85	−454.8	−138.1
Nitrate ion	NO₃⁻	aqueous	−205.0	−108.74	146.4
Phosphate ionNBS lists S° to the nearest J/(mol·K); newer tables differ by a joule or two	PO₄³⁻	aqueous	−1277.4	−1018.7	−222
Potassium ion	K⁺	aqueous	−252.38	−283.27	102.5
Silver ion	Ag⁺	aqueous	105.579	77.107	72.68
Sodium ionS° follows the NBS 1982 evaluation; newer tables differ by about a joule	Na⁺	aqueous	−240.12	−261.905	59.0
Sulfate ion	SO₄²⁻	aqueous	−909.27	−744.53	20.1
Zinc ion	Zn²⁺	aqueous	−153.89	−147.06	−112.1

AluminumAl (s)
ΔH_f°
0
ΔG_f°
0
S°
28.33
BromineBr₂ (l)
ΔH_f°
0
ΔG_f°
0
S°
152.231
BromineBr₂ (g)
ΔH_f°
30.907
ΔG_f°
3.110
S°
245.463
Gas phase, not the reference state of bromine
Bromine atomBr (g)
ΔH_f°
111.884
ΔG_f°
82.396
S°
175.022
Gaseous atom, used for atomization enthalpies
Calcium (α)Ca (s)
ΔH_f°
0
ΔG_f°
0
S°
41.42
Carbon (graphite)C (s)
ΔH_f°
0
ΔG_f°
0
S°
5.740
Reference state of carbon
Carbon (diamond)C (s)
ΔH_f°
1.895
ΔG_f°
2.900
S°
2.377
Not the reference state, so ΔHf° is not zero
Carbon atomC (g)
ΔH_f°
716.682
ΔG_f°
671.257
S°
158.096
Gaseous atom, used for atomization enthalpies
ChlorineCl₂ (g)
ΔH_f°
0
ΔG_f°
0
S°
223.066
Chlorine atomCl (g)
ΔH_f°
121.679
ΔG_f°
105.680
S°
165.198
Gaseous atom, used for atomization enthalpies
CopperCu (s)
ΔH_f°
0
ΔG_f°
0
S°
33.150
FluorineF₂ (g)
ΔH_f°
0
ΔG_f°
0
S°
202.78
Fluorine atomF (g)
ΔH_f°
78.99
ΔG_f°
61.91
S°
158.754
Gaseous atom, used for atomization enthalpies
HydrogenH₂ (g)
ΔH_f°
0
ΔG_f°
0
S°
130.684
Hydrogen atomH (g)
ΔH_f°
217.965
ΔG_f°
203.247
S°
114.713
Gaseous atom, used for atomization enthalpies
IodineI₂ (s)
ΔH_f°
0
ΔG_f°
0
S°
116.135
IodineI₂ (g)
ΔH_f°
62.438
ΔG_f°
19.327
S°
260.69
Gas phase, not the reference state of iodine
IronFe (s)
ΔH_f°
0
ΔG_f°
0
S°
27.28
LeadPb (s)
ΔH_f°
0
ΔG_f°
0
S°
64.81
LithiumLi (s)
ΔH_f°
0
ΔG_f°
0
S°
29.12
MagnesiumMg (s)
ΔH_f°
0
ΔG_f°
0
S°
32.68
ManganeseMn (s)
ΔH_f°
0
ΔG_f°
0
S°
32.01
MercuryHg (l)
ΔH_f°
0
ΔG_f°
0
S°
76.02
NitrogenN₂ (g)
ΔH_f°
0
ΔG_f°
0
S°
191.61
Nitrogen atomN (g)
ΔH_f°
472.704
ΔG_f°
455.563
S°
153.298
Gaseous atom, used for atomization enthalpies
OxygenO₂ (g)
ΔH_f°
0
ΔG_f°
0
S°
205.138
Oxygen atomO (g)
ΔH_f°
249.170
ΔG_f°
231.731
S°
161.055
Gaseous atom, used for atomization enthalpies
OzoneO₃ (g)
ΔH_f°
142.7
ΔG_f°
163.2
S°
238.93
Allotrope of O2, not the reference state
Phosphorus (white)P (s)
ΔH_f°
0
ΔG_f°
0
S°
41.09
Reference state of phosphorus (white); formula written as P
PotassiumK (s)
ΔH_f°
0
ΔG_f°
0
S°
64.18
SiliconSi (s)
ΔH_f°
0
ΔG_f°
0
S°
18.83
SilverAg (s)
ΔH_f°
0
ΔG_f°
0
S°
42.55
SodiumNa (s)
ΔH_f°
0
ΔG_f°
0
S°
51.21
Sulfur (rhombic)S (s)
ΔH_f°
0
ΔG_f°
0
S°
31.80
Tin (white)Sn (s)
ΔH_f°
0
ΔG_f°
0
S°
51.55
ZincZn (s)
ΔH_f°
0
ΔG_f°
0
S°
41.63
Aluminum oxide (corundum)Al₂O₃ (s)
ΔH_f°
−1675.7
ΔG_f°
−1582.3
S°
50.92
Calcium oxideCaO (s)
ΔH_f°
−635.09
ΔG_f°
−604.03
S°
39.75
Carbon dioxideCO₂ (g)
ΔH_f°
−393.509
ΔG_f°
−394.359
S°
213.74
Carbon monoxideCO (g)
ΔH_f°
−110.525
ΔG_f°
−137.168
S°
197.674
Copper(I) oxideCu₂O (s)
ΔH_f°
−168.6
ΔG_f°
−146.0
S°
93.14
NIST WebBook lists −170.71 kJ/mol from a different source
Copper(II) oxideCuO (s)
ΔH_f°
−157.3
ΔG_f°
−129.7
S°
42.63
NIST WebBook lists −156.06 kJ/mol from a different source
Dinitrogen monoxideN₂O (g)
ΔH_f°
82.05
ΔG_f°
104.20
S°
219.85
Dinitrogen tetroxideN₂O₄ (g)
ΔH_f°
9.16
ΔG_f°
97.89
S°
304.29
Hydrogen peroxideH₂O₂ (l)
ΔH_f°
−187.78
ΔG_f°
−120.35
S°
109.6
Iron(II,III) oxide (magnetite)Fe₃O₄ (s)
ΔH_f°
−1118.4
ΔG_f°
−1015.4
S°
146.4
Iron(III) oxide (hematite)Fe₂O₃ (s)
ΔH_f°
−824.2
ΔG_f°
−742.2
S°
87.40
Lead(II) oxide (red)PbO (s)
ΔH_f°
−218.99
ΔG_f°
−188.93
S°
66.5
Lead(II) oxide (yellow)PbO (s)
ΔH_f°
−217.32
ΔG_f°
−187.89
S°
68.70
Lithium oxideLi₂O (s)
ΔH_f°
−597.94
ΔG_f°
−561.18
S°
37.57
Magnesium oxide (periclase)MgO (s)
ΔH_f°
−601.70
ΔG_f°
−569.43
S°
26.94
Manganese(IV) oxideMnO₂ (s)
ΔH_f°
−520.03
ΔG_f°
−465.14
S°
53.05
Mercury(II) oxide (red)HgO (s)
ΔH_f°
−90.83
ΔG_f°
−58.539
S°
70.29
Nitrogen dioxideNO₂ (g)
ΔH_f°
33.18
ΔG_f°
51.31
S°
240.06
Nitrogen monoxideNO (g)
ΔH_f°
90.25
ΔG_f°
86.55
S°
210.761
Silicon dioxide (quartz)SiO₂ (s)
ΔH_f°
−910.94
ΔG_f°
−856.64
S°
41.84
Silver oxideAg₂O (s)
ΔH_f°
−31.05
ΔG_f°
−11.20
S°
121.3
Sodium oxideNa₂O (s)
ΔH_f°
−414.22
ΔG_f°
−375.46
S°
75.06
NIST WebBook lists −417.98 kJ/mol
Sulfur dioxideSO₂ (g)
ΔH_f°
−296.830
ΔG_f°
−300.194
S°
248.22
Sulfur trioxideSO₃ (g)
ΔH_f°
−395.72
ΔG_f°
−371.06
S°
256.76
WaterH₂O (l)
ΔH_f°
−285.830
ΔG_f°
−237.129
S°
69.91
Water vaporH₂O (g)
ΔH_f°
−241.818
ΔG_f°
−228.572
S°
188.825
Zinc oxideZnO (s)
ΔH_f°
−348.28
ΔG_f°
−318.30
S°
43.64
NIST WebBook lists −350.46 kJ/mol from a different source
AmmoniaNH₃ (g)
ΔH_f°
−46.11
ΔG_f°
−16.45
S°
192.45
HydrazineN₂H₄ (l)
ΔH_f°
50.63
ΔG_f°
149.34
S°
121.21
Hydrogen bromideHBr (g)
ΔH_f°
−36.40
ΔG_f°
−53.45
S°
198.695
Hydrogen chlorideHCl (g)
ΔH_f°
−92.307
ΔG_f°
−95.299
S°
186.908
Hydrogen cyanideHCN (g)
ΔH_f°
135.1
ΔG_f°
124.7
S°
201.78
Hydrogen fluorideHF (g)
ΔH_f°
−271.1
ΔG_f°
−273.2
S°
173.779
Newer evaluations give about −273.3 kJ/mol (NIST WebBook)
Hydrogen iodideHI (g)
ΔH_f°
26.48
ΔG_f°
1.70
S°
206.594
Hydrogen sulfideH₂S (g)
ΔH_f°
−20.63
ΔG_f°
−33.56
S°
205.79
Nitric acidHNO₃ (l)
ΔH_f°
−174.10
ΔG_f°
−80.71
S°
155.60
PhosphinePH₃ (g)
ΔH_f°
5.4
ΔG_f°
13.4
S°
210.23
SilaneSiH₄ (g)
ΔH_f°
34.3
ΔG_f°
56.9
S°
204.62
Sulfuric acidH₂SO₄ (l)
ΔH_f°
−813.989
ΔG_f°
−690.003
S°
156.904
Ammonium chlorideNH₄Cl (s)
ΔH_f°
−314.43
ΔG_f°
−202.87
S°
94.6
Ammonium nitrateNH₄NO₃ (s)
ΔH_f°
−365.56
ΔG_f°
−183.87
S°
151.08
Ammonium sulfate(NH₄)₂SO₄ (s)
ΔH_f°
−1180.85
ΔG_f°
−901.67
S°
220.1
Calcium carbonate (calcite)CaCO₃ (s)
ΔH_f°
−1206.92
ΔG_f°
−1128.79
S°
92.9
Calcium carbonate (aragonite)CaCO₃ (s)
ΔH_f°
−1207.13
ΔG_f°
−1127.75
S°
88.7
Calcium chlorideCaCl₂ (s)
ΔH_f°
−795.8
ΔG_f°
−748.1
S°
104.6
Calcium fluorideCaF₂ (s)
ΔH_f°
−1219.6
ΔG_f°
−1167.3
S°
68.87
NIST WebBook lists −1225.91 kJ/mol
Calcium hydroxideCa(OH)₂ (s)
ΔH_f°
−986.09
ΔG_f°
−898.49
S°
83.39
Calcium sulfate (anhydrite)CaSO₄ (s)
ΔH_f°
−1434.11
ΔG_f°
−1321.79
S°
106.7
Copper(II) sulfateCuSO₄ (s)
ΔH_f°
−771.36
ΔG_f°
−661.8
S°
109
Copper(II) sulfideCuS (s)
ΔH_f°
−53.1
ΔG_f°
−53.6
S°
66.5
Iron disulfide (pyrite)FeS₂ (s)
ΔH_f°
−178.2
ΔG_f°
−166.9
S°
52.93
Lead(II) sulfatePbSO₄ (s)
ΔH_f°
−919.94
ΔG_f°
−813.14
S°
148.57
Lead(II) sulfidePbS (s)
ΔH_f°
−100.4
ΔG_f°
−98.7
S°
91.2
NIST WebBook lists −98.32 kJ/mol from a different source
Lithium chlorideLiCl (s)
ΔH_f°
−408.61
ΔG_f°
−384.37
S°
59.33
Magnesium carbonate (magnesite)MgCO₃ (s)
ΔH_f°
−1095.8
ΔG_f°
−1012.1
S°
65.7
NIST WebBook lists −1111.69 kJ/mol
Magnesium chlorideMgCl₂ (s)
ΔH_f°
−641.32
ΔG_f°
−591.79
S°
89.62
Magnesium hydroxideMg(OH)₂ (s)
ΔH_f°
−924.54
ΔG_f°
−833.51
S°
63.18
Phosphorus pentachloridePCl₅ (g)
ΔH_f°
−374.9
ΔG_f°
−305.0
S°
364.58
Phosphorus trichloridePCl₃ (l)
ΔH_f°
−319.7
ΔG_f°
−272.3
S°
217.1
Phosphorus trichloridePCl₃ (g)
ΔH_f°
−287.0
ΔG_f°
−267.8
S°
311.78
NIST WebBook lists −288.7 kJ/mol
Potassium bromideKBr (s)
ΔH_f°
−393.798
ΔG_f°
−380.66
S°
95.90
Potassium chlorateKClO₃ (s)
ΔH_f°
−397.73
ΔG_f°
−296.25
S°
143.1
Potassium chlorideKCl (s)
ΔH_f°
−436.747
ΔG_f°
−409.14
S°
82.59
Potassium fluorideKF (s)
ΔH_f°
−567.27
ΔG_f°
−537.75
S°
66.57
Potassium hydroxideKOH (s)
ΔH_f°
−424.764
ΔG_f°
−379.08
S°
78.9
Potassium iodideKI (s)
ΔH_f°
−327.900
ΔG_f°
−324.892
S°
106.32
NBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°
Potassium nitrateKNO₃ (s)
ΔH_f°
−494.63
ΔG_f°
−394.86
S°
133.05
Potassium sulfateK₂SO₄ (s)
ΔH_f°
−1437.79
ΔG_f°
−1321.37
S°
175.56
NBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°
Silicon tetrachlorideSiCl₄ (l)
ΔH_f°
−687.0
ΔG_f°
−619.84
S°
239.7
Silicon tetrafluorideSiF₄ (g)
ΔH_f°
−1614.94
ΔG_f°
−1572.65
S°
282.49
Silver bromideAgBr (s)
ΔH_f°
−100.37
ΔG_f°
−96.90
S°
107.1
Silver chlorideAgCl (s)
ΔH_f°
−127.068
ΔG_f°
−109.789
S°
96.2
Silver iodideAgI (s)
ΔH_f°
−61.84
ΔG_f°
−66.19
S°
115.5
Silver nitrateAgNO₃ (s)
ΔH_f°
−124.39
ΔG_f°
−33.41
S°
140.92
Sodium bicarbonateNaHCO₃ (s)
ΔH_f°
−950.81
ΔG_f°
−851.0
S°
101.7
NBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°
Sodium bromideNaBr (s)
ΔH_f°
−361.062
ΔG_f°
−348.983
S°
86.82
Sodium carbonateNa₂CO₃ (s)
ΔH_f°
−1130.68
ΔG_f°
−1044.44
S°
134.98
NBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°
Sodium chlorideNaCl (s)
ΔH_f°
−411.153
ΔG_f°
−384.138
S°
72.13
Sodium fluorideNaF (s)
ΔH_f°
−573.647
ΔG_f°
−543.494
S°
51.46
NIST WebBook lists −575.38 kJ/mol
Sodium hydroxideNaOH (s)
ΔH_f°
−425.609
ΔG_f°
−379.494
S°
64.455
Sodium iodideNaI (s)
ΔH_f°
−287.78
ΔG_f°
−286.06
S°
98.53
NBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°
Sodium nitrateNaNO₃ (s)
ΔH_f°
−467.85
ΔG_f°
−367.00
S°
116.52
Sodium nitriteNaNO₂ (s)
ΔH_f°
−358.65
ΔG_f°
−284.55
S°
103.8
Sodium sulfateNa₂SO₄ (s)
ΔH_f°
−1387.08
ΔG_f°
−1270.16
S°
149.58
NBS relaxes the G-H-S constraint for this row: ΔGf° is not exactly ΔHf° − TΔSf°
Zinc sulfateZnSO₄ (s)
ΔH_f°
−982.8
ΔG_f°
−871.5
S°
110.5
NIST WebBook lists −980.14 kJ/mol from a different source
Zinc sulfide (sphalerite)ZnS (s)
ΔH_f°
−205.98
ΔG_f°
−201.29
S°
57.7
BenzeneC₆H₆ (l)
ΔH_f°
49.0
ΔG_f°
124.5
S°
173.26
ΔHf° and S° from NIST WebBook; ΔGf° computed from them; ΔHf° is the WebBook review value, consistent with the two combustion measurements
EthaneC₂H₆ (g)
ΔH_f°
−84.68
ΔG_f°
−32.82
S°
229.60
Ethene (ethylene)C₂H₄ (g)
ΔH_f°
52.26
ΔG_f°
68.15
S°
219.56
Ethyne (acetylene)C₂H₂ (g)
ΔH_f°
226.73
ΔG_f°
209.20
S°
200.94
HexaneC₆H₁₄ (l)
ΔH_f°
−198.7
ΔG_f°
−4.0
S°
296.06
ΔHf° and S° from NIST WebBook; ΔGf° computed from them
HexaneC₆H₁₄ (g)
ΔH_f°
−167.1
ΔG_f°
0
S°
388.82
ΔHf° and S° from NIST WebBook; ΔGf° computed from them
MethaneCH₄ (g)
ΔH_f°
−74.81
ΔG_f°
−50.72
S°
186.264
OctaneC₈H₁₈ (l)
ΔH_f°
−250.3
ΔG_f°
6.4
S°
361.20
ΔHf° and S° from NIST WebBook; ΔGf° computed from them
OctaneC₈H₁₈ (g)
ΔH_f°
−208.7
ΔG_f°
16.4
S°
467.06
ΔHf° and S° from NIST WebBook; ΔGf° computed from them
PentaneC₅H₁₂ (l)
ΔH_f°
−173.5
ΔG_f°
−9.7
S°
263.47
ΔHf° and S° from NIST WebBook; ΔGf° computed from them
PentaneC₅H₁₂ (g)
ΔH_f°
−146.8
ΔG_f°
−8.2
S°
347.82
ΔHf° and S° from NIST WebBook; ΔGf° computed from them
TolueneC₇H₈ (l)
ΔH_f°
12.0
ΔG_f°
114.0
S°
220.96
ΔHf° and S° from NIST WebBook; ΔGf° computed from them; ΔHf° is the WebBook review value
1-PropanolC₃H₇OH (l)
ΔH_f°
−302.54
ΔG_f°
−168.5
S°
192.8
ΔHf° and S° from NIST WebBook; ΔGf° computed from them; WebBook lists S° of 192.8 and 214.2 J/(mol·K) from different studies, the first listed is used
AcetaldehydeCH₃CHO (g)
ΔH_f°
−166.19
ΔG_f°
−128.86
S°
250.3
NIST WebBook lists −170.7 kJ/mol
Acetic acidCH₃COOH (l)
ΔH_f°
−484.5
ΔG_f°
−389.9
S°
159.8
AcetoneC₃H₆O (l)
ΔH_f°
−249.4
ΔG_f°
−156.5
S°
200.4
ΔHf° and S° from NIST WebBook; ΔGf° computed from them; WebBook lists several S° values between 200.0 and 217.6, the first listed is used
Carbon disulfideCS₂ (l)
ΔH_f°
89.70
ΔG_f°
65.27
S°
151.34
Carbon tetrachlorideCCl₄ (l)
ΔH_f°
−135.44
ΔG_f°
−65.21
S°
216.40
Newer evaluations give about −128 kJ/mol (NIST WebBook)
ChloroformCHCl₃ (l)
ΔH_f°
−134.47
ΔG_f°
−73.66
S°
201.7
ChloromethaneCH₃Cl (g)
ΔH_f°
−80.83
ΔG_f°
−57.37
S°
234.58
EthanolC₂H₅OH (l)
ΔH_f°
−277.69
ΔG_f°
−174.78
S°
160.7
NIST WebBook lists −276.0 kJ/mol
EthanolC₂H₅OH (g)
ΔH_f°
−235.10
ΔG_f°
−168.49
S°
282.70
Ethylene glycol(CH₂OH)₂ (l)
ΔH_f°
−454.80
ΔG_f°
−323.08
S°
166.9
FormaldehydeHCHO (g)
ΔH_f°
−108.57
ΔG_f°
−102.53
S°
218.77
Formic acidHCOOH (l)
ΔH_f°
−424.72
ΔG_f°
−361.35
S°
128.95
MethanolCH₃OH (l)
ΔH_f°
−238.66
ΔG_f°
−166.27
S°
126.8
MethanolCH₃OH (g)
ΔH_f°
−200.66
ΔG_f°
−161.96
S°
239.81
NIST WebBook lists −205.0 kJ/mol
MethylamineCH₃NH₂ (g)
ΔH_f°
−22.97
ΔG_f°
32.16
S°
243.41
SucroseC₁₂H₂₂O₁₁ (s)
ΔH_f°
−2221.2
ΔG_f°
−1552.7
S°
392.4
ΔHf° and S° from NIST WebBook; ΔGf° computed from them; ΔHf° is a single combustion measurement (1939)
UreaCO(NH₂)₂ (s)
ΔH_f°
−333.51
ΔG_f°
−197.33
S°
104.60
Acetate ionCH₃COO⁻ (aq)
ΔH_f°
−486.01
ΔG_f°
−369.31
S°
86.6
Aluminum ionAl³⁺ (aq)
ΔH_f°
−531
ΔG_f°
−485
S°
−321.7
NBS lists ΔHf° and ΔGf° to the nearest kJ/mol
Ammonium ionNH₄⁺ (aq)
ΔH_f°
−132.51
ΔG_f°
−79.31
S°
113.4
Bromide ionBr⁻ (aq)
ΔH_f°
−121.55
ΔG_f°
−103.96
S°
82.4
Calcium ionCa²⁺ (aq)
ΔH_f°
−542.83
ΔG_f°
−553.58
S°
−53.1
Carbonate ionCO₃²⁻ (aq)
ΔH_f°
−677.14
ΔG_f°
−527.81
S°
−56.9
Chloride ionCl⁻ (aq)
ΔH_f°
−167.159
ΔG_f°
−131.228
S°
56.5
Copper(II) ionCu²⁺ (aq)
ΔH_f°
64.77
ΔG_f°
65.49
S°
−99.6
Fluoride ionF⁻ (aq)
ΔH_f°
−332.63
ΔG_f°
−278.79
S°
−13.8
Hydrogen carbonate ionHCO₃⁻ (aq)
ΔH_f°
−691.99
ΔG_f°
−586.77
S°
91.2
Hydrogen ionH⁺ (aq)
ΔH_f°
0
ΔG_f°
0
S°
0
Defined as zero for every property (1 mol/kg standard state)
Hydrogen sulfate ionHSO₄⁻ (aq)
ΔH_f°
−887.34
ΔG_f°
−755.91
S°
131.8
Hydroxide ionOH⁻ (aq)
ΔH_f°
−229.994
ΔG_f°
−157.244
S°
−10.75
Iodide ionI⁻ (aq)
ΔH_f°
−55.19
ΔG_f°
−51.57
S°
111.3
Iron(II) ionFe²⁺ (aq)
ΔH_f°
−89.1
ΔG_f°
−78.90
S°
−137.7
Iron(III) ionFe³⁺ (aq)
ΔH_f°
−48.5
ΔG_f°
−4.7
S°
−315.9
Lithium ionLi⁺ (aq)
ΔH_f°
−278.49
ΔG_f°
−293.31
S°
13.4
Magnesium ionMg²⁺ (aq)
ΔH_f°
−466.85
ΔG_f°
−454.8
S°
−138.1
Nitrate ionNO₃⁻ (aq)
ΔH_f°
−205.0
ΔG_f°
−108.74
S°
146.4
Phosphate ionPO₄³⁻ (aq)
ΔH_f°
−1277.4
ΔG_f°
−1018.7
S°
−222
NBS lists S° to the nearest J/(mol·K); newer tables differ by a joule or two
Potassium ionK⁺ (aq)
ΔH_f°
−252.38
ΔG_f°
−283.27
S°
102.5
Silver ionAg⁺ (aq)
ΔH_f°
105.579
ΔG_f°
77.107
S°
72.68
Sodium ionNa⁺ (aq)
ΔH_f°
−240.12
ΔG_f°
−261.905
S°
59.0
S° follows the NBS 1982 evaluation; newer tables differ by about a joule
Sulfate ionSO₄²⁻ (aq)
ΔH_f°
−909.27
ΔG_f°
−744.53
S°
20.1
Zinc ionZn²⁺ (aq)
ΔH_f°
−153.89
ΔG_f°
−147.06
S°
−112.1

Source: NBS Tables of Chemical Thermodynamic Properties (Wagman et al., 1982), 298.15 K and 1 bar. ΔHf° and S° of the larger organic compounds are from the NIST Chemistry WebBook; their ΔGf° is computed from them. ΔH_f° and ΔG_f° in kJ/mol, S° in J/(mol·K). Aqueous ions are in the standard state of 1 mol/kg with H⁺(aq) defined as zero, and their S° values follow the NBS evaluation. Print splits the table into pages of 16 rows. The Reactant and Product buttons send a row to the reaction calculator.

Free Enthalpy of Formation Charts

Every chart below is drawn from the same data as the tool above. View, download and print them free, no sign-up.

Quick reference

Enthalpy of Formation Quick Reference: Common Substances

The substances students meet most often, one sheet, with ΔHf°, ΔGf° and S° at 298.15 K.

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Reference charts

Worked examples

Printable versions

What the standard enthalpy of formation is

The standard enthalpy of formation, ΔHf°, is the heat change when one mole of a compound forms from its elements, each in its reference state (usually its most stable form) at 298.15 K and 1 bar. Forming liquid water from hydrogen gas and oxygen gas releases heat, so ΔHf°(H₂O, l) is −285.830 kJ/mol. Forming carbon dioxide from graphite and oxygen gives −393.509 kJ/mol. A negative value means the compound is lower in enthalpy than its elements, and a positive value, such as 226.73 kJ/mol for ethyne, means it is higher.
An element in its reference state has ΔHf° = 0 by definition, because nothing has to happen to make it. That is why O₂(g), H₂(g), Br₂(l) and graphite are zero. Other forms of the same element are not: diamond is 1.895 kJ/mol and ozone is 142.7 kJ/mol relative to graphite and O₂. The state matters too. Water vapor is −241.818 kJ/mol and liquid water is −285.830 kJ/mol, and the gap is the heat of vaporization at 298 K.

How to calculate a reaction enthalpy from the table

Write the balanced equation, look up ΔHf° for every species in the right state, multiply each by its coefficient, and subtract: ΔH°rxn = ΣnΔHf°(products) − ΣnΔHf°(reactants). The same pattern works for ΔG° with the ΔGf° column and for ΔS° with the S° column, except that S° of an element is not zero.
Example 1, methane burning to liquid water: CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l). The products sum to −965.2 kJ/mol and the reactants to −74.8 kJ/mol, so ΔH° = −890.4 kJ/mol. If the water leaves as vapor, the same fuel gives −802.3 kJ/mol, which is why a fuel has a higher and a lower heating value.
Example 2, the thermite reaction: Fe₂O₃(s) + 2Al(s) → Al₂O₃(s) + 2Fe(s). The elements Al and Fe are zero, so ΔH° = −1675.7 − (−824.2) = −851.5 kJ/mol, with ΔG° of −840.1 kJ/mol. The calculator on this page does the same sums and refuses an unbalanced equation.

Gibbs energy, entropy and spontaneity

The ΔGf° column tells you whether a reaction is spontaneous at 298 K: a negative ΔG°rxn means the reaction runs as written under standard conditions. The two are linked by ΔG° = ΔH° − TΔS°, so you can check a table row yourself. For the methane example the calculator shows ΔS° = −243.0 J/(mol·K), and ΔH° − TΔS° at 298.15 K gives −817.9 kJ/mol, matching the ΔG° from the ΔGf° column to rounding. A reaction can be exothermic and still non-spontaneous at high temperature if ΔS° is very negative, and an endothermic one can run when ΔS° is large and positive.

Formation enthalpies versus bond energies

Bond energies are averages taken over many molecules in the gas phase, so they give a quick estimate. Formation enthalpies are measured for the specific compound and are far more reliable. The table can also give you bond information: atomizing methane, CH₄(g) → C(g) + 4H(g), costs 716.682 + 4 × 217.965 − (−74.81) = 1663.4 kJ/mol, which is about 415.8 kJ/mol per C–H bond. Use the table whenever the compounds are listed, and bond energies only when they are not.

1 bar versus 1 atm, and where the values come from

Current convention sets the standard pressure at 1 bar (0.1 MPa). Older textbooks used 1 atm (101.325 kPa). The difference is 1.3 percent in pressure, and it changes ΔHf° of gases by a negligible amount and S° of a gas by only about 0.1 J/(mol·K), so the two sets of values can be used together for coursework. Most values here come from the NBS Tables of Chemical Thermodynamic Properties (Wagman and co-authors, 1982), the standard evaluated source, cross-checked against the NIST Chemistry WebBook where it lists the substance. The NBS tables cover few organic compounds beyond C2, so ΔHf° and S° of pentane, hexane, octane, benzene, toluene, acetone, 1-propanol and sucrose are taken from the NIST Chemistry WebBook, and their ΔGf° is computed from ΔHf°, S° and the entropies of the elements. Newer evaluations differ for a few species by a kilojoule or two, and aqueous ions use the convention that H⁺(aq) is zero. If your course gives its own table, use that one for exams.

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