Standard state and enthalpy of formation, Gibbs free energy of formation, entropy and heat capacity

Definition and explanation of the terms standard state and standard enthalpy of formation, with listing of values for standard enthalpy and Gibbs free energy of formation, as well as standard entropy and molar heat capacity, of 370 inorganic compounds

The term standard state is used to describe a reference state for substances, and is a help in thermodynamical calculations (as enthalpy, entropy and Gibbs free energy calculations). The superscript degree symbol (°) indicates that substances are in their standard states. (ΔH°, ΔG°, S°.....)

Definitions of standard states:

  • For a gas, the standard state is as a pure gaseous substance as a (hypothetical) ideal gas at a pressure of exactly 1 bar.
  • For a substance present in a solution, the standard state is a concentration of exactly 1 M at an applied pressure of 1 bar, but exhibiting infinite-dilution behavior. (Hence taking infinite-dilution behavior to be the standard state allows corrections for non-ideality to be made consistently for all the different solutes.)
  • For a pure substance in a condensed state (liquid or solid), the standard state is the pure liquid or solid under 1 bar pressure.
  • For an element the standard state is the form in which the element exists (is more stable) under condition of 1 bar and at the temperature of interest (usually 25°C).
    • ΔH0f for an element in its standard state is zero. Thus, elements in their standard states are not included in the ΔHreaction calculations.

Note! Standard state is NOT the same as standard temperature and pressure (STP) for a gas, and must not be confused with this term.

Enthalpy is a state function, defined by the internal energy (E), the pressure (P) and volume (V) of a system:

H = E + PV  and  ΔH = ΔE + Δ(PV)

For enthalpy, there are no method to determine absolute values, only enthalpy changes (ΔH values) can be measured. Then it is important to have a common and  well defined reference state. Since enthalpy is a state function, a change in enthalpy does not depend on the pathway between two states.

Hess's law: In going from a particular set of reactants to a particular set of products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps.

At constant pressure:    ΔH  = q   (qp = heat from or to the chemical system at constant pressure,  q is also called heat of reaction)

Exothermic reaction:     negative ΔH    (heat transferred to the surroundings from the system)

Endothermic reaction:  positive  ΔH    (heat adsorbed by the system from the surroundings)

The standard enthalpy of formation (ΔH0f) of a compound is the change in enthalpy that accompanies the formation of 1 mole of a compound from its elements with all substances in their standard states.

The table below  shows the standard enthalpy of formation, the standard Gibbs free energy of formation, standard entropy and molar heat capacity at constant pressure of several inorganic compounds.

See also Standard enthalpy of formation, Gibbs free energy of formation, entropy and molar heat capacity of organic substances  and Thermodyamics key values internationally agreed for tabulation of more of the same type of values

Substance ΔH0f @25°C
(kJ/mol)
ΔG0f @25°C
(kJ/mol)
S0 @25°C
(J/(molK))
Cp @25°C
J/(mol K)
Ag(g) 284.9 246 173 20.8
Ag(s) 0 0 42.6 25.4
Ag+(aq) 105.8 77.1 73.5
AgCN(s) 146 156.9 107.2 66.7
Ag2CO3(s) -505.8 -436.8 167.4 112.3
AgNO3(s) −124.4 −33.4 140.9 93.1
Ag2O(s) −31.1 −11.2 121.3 65.9
Ag2S(s) −32.6 −40.7 144 76.5
AgBr(s) −100.4 −96.9 107.1 52.4
AgCl(s) −127.0 −109.8 96.3 50.8
AgF(s) -204.6 -187 84
AgI(s) -61.8 -66.2 115.5 56.8
Al(g) 330 289.4 164.6 21.4
Al(s) 0 0 28.3 24.2
Al2O3(s) −1675.7 −1582.3 50.9 79.0
AlF3(s) -1510.4 -1431.1 66.5 75.1
AlI3(s) -302.9 195.9
AlBr3(s) -527.2 180.2 100.6
AlCl3(s) −704.5 −628.11 112.3 91.1
Al(OH)3(s) -1277
Al(OH)4-(aq) -1490 -1297 117
AlPO4(s) -1733.8 -1617.9 90.8 93.2
Ar(g) 0 154.9 20.8
B(s) 0 0 5.9 11.1
B(g) 565 521.0 153.4 20.8
BH(g) 442.7 412.7 171.8 29.2
BH3(g) 89.2 93.3 188.2 36.0
B2S3(s) -240.6 100.0 111.7
Ba(g) 180 146 170.2
Ba(s) 0 0 62.5 28.1
BaCO3(s) −1213.0 −1134.4 112.1 86.0
BaH2(s) -177 -138.2 63.0
BaBr2(s) -757.3 -736.8 146.0
BaCl2(s) -855 -806.7 123.7 75.1
BaF2(s) -1207.1 -1156.8 96.4 71.2
BaI2(s) -602.1 -597 167.0
BaO(s) −548.0 −520.3 72.1 47.3
BaSO4(s) −1473.2 −1362.2 132.2 101.8
Be(g) 324 286.6 136.3 20.8
Be(s) 0 0 9.5 13.4
BeBr2(s) -353.5 108 69.4
BeCl2(s) -490.4 -445.6 75.8 62.4
BeF2(s) -1026.8 -979.4 53.4 51.8
BeI2(s) -192.5 121 71.1
BeO(s) −609.4 −580.1 13.8 25.6
Be(OH)2(s) −902.5 −815.0 45.5 62.1
BeSO4(s) -1205.2 -1093.8 77.9 85.7
Bi(g) 207.1 168.2 187 20.8
Bi(s) 0 0 56.7 25.5
Bi2O3(s) -573.9 -493.7 151.5 113.5
BiCl3(s) -379.1 -315.0 177.0 105.0
Br(aq) −121.4 −104.0 82.6
Br(g) 111.9 82.4 175 20.8
Br2(g) 30.9 3.1 245.5 36.0
Br2(l) 0 0 152.2 75.7
BrCl(g) 14.6 -1 240.1 35.0
BrF(g) -93.8 -109.2 229 33.0
BrF3(g) -1136 1119.4 254.4 66.6
C(g) 716.7 671.3 158.1 0.8
C(s, diamond) 1.9 2.9 2.4 6.1
C(s, graphite) 0 0 5.7 8.5
CBr4(g) 83.9 67 358.1
CBr4(s) 29.4 47.7 212.5
CCl2F2(g) −477.4 −439.4 300.8
CCl2O(g) −219.1 −204.9 283.5
CCl4(g) −95.7 −53.6 309.9
CCl4(l) −128.2 −62.6 216.2
CF4(g) −933.6 −888.3 261.6
CS2(g) 116.7 67.1 237.8 45.4
CS2(l) 89 64.6 151.3 76.4
CO(g) −110.5 −137.2 197.7 29.1
CO2(g) −393.5 −394.4 213.8 37.1
Ca(g) 177.8 144 154.9 20.8
Ca(s) 0 0 41.6 25.9
Ca(OH)2(s) −985.2 −897.5 83.4 87.5
CaBr2(s) -682.8 -663.6 130
CaCl2(s) −795.4 −748.8 108.4 72.9
CaCN(s) -184.5
CaCO3(s, aragonite) −1207.8 −1128.2 88 82.3
CaCO3(s, calcite) −1207.6 −1129.1 91.7 83.5
CaF2(s) −1228.0 −1175.6 68.5 67.0
CaH2(s) -181.5 -142.5 41.4 41.0
CaI2(s) -533.5 -528.9 142
CaO(s) −634.9 −603.3 38.1 42.0
CaSO4(s) −1434.5 −1322.0 106.5 99.7
Cd(g) 111.8 167.7 20.8
Cd(s) 0 0 51.8 26.0
CdBr2(s) -316.2 -296.3 137.2 76.7
CdCl2(s) −391.5 −343.9 115.3 74.7
CdCO3(s) -750.6 -669.4 92.5
CdF2(s) -700.4 -647.7 77.4
CdS(s) −161.9 −156.5 64.9
CdSO4(s) -933.3 -822.7 123.0 99.6
Cl(aq) −167.1 −131.2 56.6
Cl(g) 121.3 105.3 165.2 21.8
Cl2(g) 0 0 223.1 33.9
ClF(g) -50.3 -51.8 217.9 32.1
ClF3(g) −163.2 −123.0 281.6 63.9
ClO2(g) 89.1 105 263.7 46.0
Cl2O(g) 80.3 97.9 266.2 45.4
Co(g) 424.7 380.3 179.5 23.0
Co(s) 0 0 30 24.8
CoCl2(s) −312.5 −269.8 109.2 78.5
Cr(g) 396.6 351.8 174.5 20.8
Cr(s) 0 0 23.8 23.4
Cr2O3(s) −1139.7 −1058.1 81.2 118.7
CrCl2(s) -395.4 -356 115.3 71.2
CrCl3(s) −556.5 −486.1 123 91.8
CrO2(g) -598
CrO3(g) −292.9 266.2 56.0
Cs(g) 76.5 49.6 175.6 20.8
Cs(s) 0 0 85.2 32.2
CsCl(s) −443.0 −414.5 101.2 52.5
Cu(g) 337.4 297.7 166.4 20.8
Cu(s) 0 0 33.2 24.2
Cu2O(s) −168.6 −146.0 93.1 63.6
CuO(s) −157.3 −129.7 42.6
Cu2S(s) −79.5 −86.2 120.9 76.3
CuS(s) -53.1 -53.6 66.5 47.8
CuSO4(s) -771.4 -662.2 109.2
CuBr(s) -104.6 -100.8 96.1 54.7
CuBr2(s) -141.8
CuCl(s) −137.2 −119.9 86.2 48.5
CuCl2(s) −220.1 −175.7 108.1 71.9
CuCN(s) 96.2 111.3 84.5
F(aq) −335.4 −278.8 −13.8
F(g) 79.4 62.3 158.8 22.7
F2(g) 0 0 202.8 32.3
F2O(g) 24.5 41.8 247.5 43.3
FO(g) 109 105.3 216.4 32.0
FB(g) -122.2 -149.8 200.5 58.6
Fe(g) 416.3 370.7 180.5 25.7
Fe(s) 0 0 27.3 25.1
FeO(s) −272.0 −251.4 60.7
Fe2+(aq) −89.1 −78.9 −137.7
Fe2O3(s) −824.2 −742.2 87.4 103.9
Fe3+(aq) −48.5 −4.7 −315.9
Fe3O4(s) −1118.4 −1015.4 146.4 143.4
FeCO3(s) −740.6 −666.7 92.9 82.1
FeS2(s) −178.2 −166.9 52.9 62.2
FeCl2(s) −341.8 −302.3 118 75.7
FeCl3(s) −399.5 −334.0 142.3 96.7
FeBr2(s) -249.8 -238.1 140.6
FeBr3(s) -268.2
Fe3C(s) 25.1 20.1 104.6 105.9
H(g) 218.0 203.3 114.7 20.8
H+(aq) 0 0 0
H2(g) 0 0 130.7 28.8
H2O(g) −241.8 −228.6 188.8 33.6
H2O(l) −285.8 −237.1 70.0 75.3
H2O2(g) −136.3 −105.6 232.7 43.1
H2O2(l) −187.8 −120.4 109.6 89.1
H2S(g) −20.6 −33.4 205.8 34.2
H2Se(g) 29.7 15.9 219 34.7
H2SO4(aq) −909.3 −744.5 20.1
H2SO4(l) -814.0 -690.0 156.9 138.9
H3PO4(l) −1271.7 −1123.6 150.8 145.0
H3PO4(s) −1284.4 −1124.3 110.5 106.1
HBr(aq) −121.6 −104.0 82.4
HBr(g) −36.3 −53.4 198.7 29.1
HCl(aq) −167.2 −131.2 56.5
HCl(g) −92.3 −95.3 186.9 29.1
HCN(g) 135.1 124.7 201.8 35.9
HCN(l) 108.9 125 112.8 70.6
HF(aq) −332.6 −278.8 −13.8
HF(g) −273.3 −275.4 173.8
HI(aq) −55.2 −51.6 111.3
HI(g) 26.5 1.7 206.6 29.2
HNO2(g) −79.5 −46.0 254.1
HNO3(aq) −207.4 −111.3 146.4
HNO3(g) −133.9 −73.5 266.9 54.1
HNO3(l) −174.1 −80.7 155.6 109.9
He(g) 0 0 126.2 20.8
Hg(g) 61.4 31.8 175
Hg(l) 0 0 75.9 28.0
Hg2(g) 108.8 68.2 288.1
HgO(s) −90.8 −58.5 70.3 44.1
HgS(s, red) −58.2 −50.6 82.4 48.4
Hg2SO4(s) -743.1 -625.8 200.7 132.0
HgSO4(s) -707.5
Hg2Cl2(s) −265.4 −210.7 191.6 191.6
HgCl2(s) −224.3 −178.6 146.0 146.0
Hg2Br2(s) -206.9 -181.1 218.0 218.0
HgBr2(s) -170.7 -153.1 172.0 172.0
Hg2I2(s) -121.3 -111 233.5 233.5
HgI2(s) -105.4 -101.7 180.0 180.0
I(aq) −56.8 −51.6 106.5
I(g) 106.8 70.2 180.8 20.8
I2(g) 62.4 19.3 260.7 36.9
I2(s) 0 0 116.1 54.4
HIO3(s) -230.1
IBr(g) 40.8 3.7 258.8 36.4
ICl(g) 17.8 -5.5 247.6 35.6
IF(g) -95.7 -118.5 236.2 33.4
K(g) 89.0 60.5 160.3 20.8
K(s) 0 0 64.7 29.6
K2CO3(s) −1151.0 −1063.5 155.5 114.4
K2O(s) −361.5 −322.1 94.1
K2O2(s) −494.1 −425.1 102.1
K2SO4(s) −1437.8 −1321.4 175.6 131.5
KBr(s) −393.8 −380.7 95.9 52.3
KCl(s) −436.5 −408.5 82.6 51.3
KF(s) -567.3 -537.8 66.6 49.0
KI(s) -327.9 -324.9 106.3 52.9
KClO3(s) −397.7 −296.3 143.1 100.3
KMnO4(s) −837.2 −737.6 171.7 117.6
KNO2(s) −369.8 −306.6 152.1 107.4
KNO3(s) −494.6 −394.9 133.1 96.4
KSCN(s) −200.2 −178.3 124.3 88.5
Kr(g) 0 0 164.1 20.8
Li(g) 159.3 126.6 138.8 20.8
Li(s) 0 0 29.1 24.9
Li+(aq) −278.5 −293.3 12.4
Li2O(s) −597.9 −561.2 37.6 54.1
LiOH(s) -487.5 -441.5 42.8 49.6
LiNO3(s) -483.1 -381.1 90.0
LiBr(s) -351.2 -342 74.3
LiCl(s) −408.6 −384.4 59.3 48.0
LiF(s) -616 -587.7 35.7 41.6
LiI(s) -270.4 -270.3 86.8 51.0
Mg(g) 147.1 112.5 148.6 20.8
Mg(s) 0 0 32.7 24.9
MgO(s) −601.6 −569.3 27.0 37.2
Mg(OH)2(s) −924.5 −833.5 63.2 77.0
MgS(s) −346.0 −341.8 50.3 45.6
MgSO4(s) −1284.9 −1170.6 91.6 96.5
MgBr2(s) -524.3 -503.8 117.2
MgCl2(s) −641.3 −591.8 89.6 71.4
MgF2(s) -1124.2 -1071.1 57.2 61.6
Mn(g) 280.7 238.5 173.7 20.8
Mn(s) 0 0 32 26.3
MnO(s) −385.2 −362.9 59.7 45.4
MnO2(s) −520.0 −465.1 53.1 54.1
MnO4(aq) −541.4 −447.2 191.2
MnBr2(s) -384.9
MnCl2(s) −481.3 −440.5 118.2 72.9
Mo(g) 658.1 612.5 182 20.8
Mo(s) 0 0 28.7 24.1
MoO2(s) −588.9 −533.0 46.3 56.0
MoO3(s) −745.1 −668.0 77.7 75.0
MoS2(s) -235.1 -225.9 62.6 63.6
MoS3(s) -364 -354 119
N(g) 472.7 455.5 153.3 20.8
N2(g) 0 0 191.6 29.1
NF3(g) −132.1 −90.6 260.8 53.4
NH3(g) −45.9 −16.4 192.8 35.1
NH4+(aq) −133.3 −79.3 111.2
NH4Cl(s) −314.4 −202.9 94.6 84.1
NH4NO3(s) −365.6 −183.9 151.1 139.3
NH4OH(l) −361.2 −254.0 165.6 154.9
(NH4)2SO4(s) −1180.9 −901.7 220.1 187.5
N2H4(g) 95.4 159.4 238.5
N2H4(l) 50.6 149.3 121.2
NO2(g) 33.2 51.3 240.1 37.2
N2O(g) 81.6 103.7 220 38.6
NO(g) 91.3 87.6 210.8
N2O4(g) 11.1 99.8 304.4 79.2
N2O4(l) −19.5 97.5 209.2 142.7
Na(g) 107.5 77 153.7 20.8
Na(s) 0 0 51.3 28.2
Na+(aq) −240.2 −261.9 58.5
Na2CO3(s) −1130.7 −1044.4 135 112.3
Na2O(s) −414.2 −375.5 75.1 69.1
Na2O2(s) −510.9 −447.7 95 89.2
Na2SO4(s) −1387.1 −1270.2 149.6 128.2
NaBr(aq) −361.7 −365.8 141.4
NaBr(g) −143.1 −177.1 241.2 36.3
NaBr(s) −361.1 −349.0 86.8 51.4
NaCl(aq) −407.3 −393.1 115.5
NaCl(s) −411.2 −384.1 72.1 50.5
NaCN(s) −87.5 −76.4 115.6 70.4
NaF(aq) −572.8 −540.7 45.2
NaF(s) −576.6 −546.3 51.1 46.9
NaN3(s) 21.7 93.8 96.9 76.6
NaNO3(aq) −447.5 −373.2 205.4
NaNO3(s) −467.9 −367.0 116.5 92.9
NaO2(s) −260.2 −218.4 115.9 72.1
NaOH(s) -425.8 -379.7 64.4 59.5
NaH(s) -56.3 -33.6 40 36.4
Ne(g) 0 0 146.3 20.8
Ni(g) 429.7 384.5 182.2 23.4
Ni(s) 0 0 29.9 26.1
Ni2O3(s) -489.5
Ni(OH)2(s) −529.7 −447.2 88
NiBr2(s) -212.1
NiCl2(s) −305.3 −259.0 97.7 71.7
NiF2(s) -651.4 -604.1 73.6 64.1
O(g) 249.2 231.7 161.1 21.9
O2(g) 0 0 205.2 29.4
O3(g) 142.7 163.2 238.9 39.2
OH(aq) −230.0 −157.2 −10.9
Os(g) 791 745 192.6 20.8
Os(s) 0 0 32.6 24.7
OsO4(g) −337.2 −292.8 293.8 74.1
OsO4(s) −394.1 −304.9 143.9
P(g, white) 316.5 280.1 163.2 20.8
P(s, black) −39.3
P(s, red)
−17.6 −12.5 22.8 21.2
P(s, white) 0 0 41.1 23.8
P2(g) 144.0 103.5 218.1
P4(g) 58.9 24.4 280.0
PCl3(g) −287.0 −267.8 311.8 71.8
PCl3(l) −319.7 −272.3 217.1
PCl5(g) −374.9 −305.0 364.6 112.8
PH3(g) 5.4 13.5 210.2 37.1
POCl3(g) −558.5 −512.9 325.5
POCl3(l) −597.1 −520.8 222.5
Pb(g) 195.2 162.2 175.4 20.8
Pb(s) 0 0 64.8 26.8
PbCl2(s) −359.4 −314.1 136
PbCO3(s) −699.1 −625.5 131 87.4
PbO(s, red or litharge) −219.0 −188.9 66.5 45.8
PbO(s, yellow or massicot) −217.3 −187.9 68.7 45.8
PbO2(s) −277.4 −217.3 68.6 64.6
Pb(NO3)2(aq) −416.3 −246.9 303.3
Pb(NO3)2(s) −451.9
PbS(s) −100.4 −98.7 91.2 49.5
PbSO4(s) −920.0 −813.0 148.5 103.2
Rb(g) 80.9 53.1 170.1 20.8
Rb(s) 0 0 76.8

31.1

RbCl(s) −435.4 −407.8 95.9 52.4
S(g, rhombic) 277.2 236.7 167.8 23.7
S(s, rhombic) 0 0 32.1 22.6
SO2(g) −296.8 −300.1 248.2 39.9
SO3(g) −395.7 −371.1 256.8 50.7
SO42−(aq) −909.3 −744.5 18.5
SOCl2(g) −212.5 −198.3 309.8
Se(g, gray) 227.1 187 176.7
Se(s, gray) 0 0 42.4 25.4
Si(g) 450 405.5 168.0 22.3
Si(s) 0 0 18.8 20.0
SiC(s, cubic) −65.3 −62.8 16.6 26.9
SiC(s, hexagonal) −62.8 −60.2 16.5 26.7
SiCl4(g) −657.0 −617.0 330.7
SiCl4(l) −687.0 −619.8 239.7
SiH4(g) 34.3 56.9 204.6 42.8
Sn(g, white) 301 266.2 168.5 21.3
Sn(s, gray) −2.1 0.1 44.1 25.8
Sn(s, white) 0 0 51.2 27.0
SnCl4(g) −471.5 −432.2 365.8 98.3
SnCl4(l) −511.3 −440.1 258.6 165.3
SnO2(s) −557.6 −515.8 49 52.6
Ti(g) 473 428.4 180.3 24.4
Ti(s) 0 0 30.7 25.1
TiCl2(s) −513.8 −464.4 87.4 69.8
TiCl3(s) −720.9 −653.5 139.7 97.2
TiCl4(g) −763 −726.3 353 95.4
TiCl4(l) −804.2 −737.2 252.3 145.2
TiO2(s) −944.0 −888.8 50.6 55.0
U(g) 533 488.4 199.8 23.7
U(s) 0 0 50.2 27.7
UF4(g) −1598.7 −1572.7 368 91.2
UF4(s) −1914.2 −1823.3 151.7 116.0
UF6(g) −2147.4 −2063.7 377.9 129.6
UF6(s) −2197.0 −2068.5 227.6 166.8
UO2(g) −465.7 −471.5 274.6 51.4
UO2(s) −1085.0 −1031.8 77.0 63.6
V(g) 514.2 754.4 182.3 26.0
V(s) 0 0 28.9 24.9
V2O5(s) −1550.6 −1419.5 131.0 127.7
VCl3(s) −580.7 −511.2 131.0 93.2
VCl4(g) −525.5 −492.0 362.4 96.2
VCl4(l) −569.4 −503.7 255.0
Xe(g) 0 0 169.7 20.8
Zn(g) 130.4 94.8 161.0 20.8
Zn(s) 0 0 41.6 25.4
ZnBr2(s) -328.7 -312.1 138.5
ZnCl2(s) -415.1 −369.4 111.5 71.3
ZnF2(s) -764.4 -713.3 73.7 65.7
ZnI2(s) -208.0 -209.0 161.1
Zn(NO3)2(s) -483.7
ZnS(s, sphalerite) -206.0 −201.3 57.7 46.0
ZnSO4(s) -982.8 −871.5 110.5 99.2
Zr(g) 608.8 566.5 181.4 26.7
Zr(s) 0 0 39 25.4
ZrCl2(s) −502.0 −386 110
ZrCl4(s) −980.5 −889.9 181.6 119.8

For conversion of units, use the Specific heat online unit converter.

See also tabulated values of specific heat capacity of gases, food and foodstuffmetals and semimetals, common liquids and fluidscommon solids, and other common substances as well as values of molar heat capacity of  common organic substances.

The specific heat capacity can be calculated from the molar heat capacity, and vise versa:

cp = Cp / M    and  

Cp = cp . M

where

cp = specific heat capacity

Cp = molar heat capacity

M = molar weight of the actual substance (g/mol).

Related Topics

  • Material Properties - Material properties for gases, fluids and solids - densities, specific heats, viscosities and more
  • Basics - The SI-system, unit converters, physical constants, drawing scales and more
  • Thermodynamics - Effects of work, heat and energy on systems

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