National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

I	Introduction
II	Experimental data
III	Calculated data
IV	Data comparisons
V	Cost comparisons
VI	Input and output files
VII	Tutorials and Units
VIII	Links to other sites
IX	Feedback
X	Older CCCBDB versions
XII	Geometries
XIII	Vibrations
XIV	Reaction data
XV	Entropy data
XVI	Bibliographic data
XVII	Ion data
XVIII	Bad calculations
XIX	Index of properties
XX	H-bond dimers
XXI	Oddities

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II.C.1. (XV.B.)

Thermodynamic reference states.

Integrated Heat Capacity (H(298)-H(0)) in kJ mol^-1

Element	Reference State	H(298)-H(0)	unc.
H	H2, g	8.468	0.001
D	D2, g	8.569
He	He, g	6.197
Li	Li, cr	4.632	0.040
Be	Be, cr	1.950	0.020
B	B, cr	1.222	0.008
C	C, cr graphite	1.050	0.020
N	N2, g	8.670	0.001
O	O2, g	8.680	0.002
F	F2, g	8.825	0.001
Ne	Ne, g	6.197
Na	Na, cr	6.460	0.020
Mg	Mg, cr	4.998	0.030
Al	Al, cr	4.540	0.020
Si	Si, cr	3.217	0.008
P	P, cr white	5.360	0.002
S	S, cr rhombic	4.412	0.006
Cl	Cl2, g	9.181	0.001
Ar	Ar, g	6.197
K	K, cr	7.082
Ti	Ti, cr	4.824	0.015
Cu	Cu, cr	5.004	0.008
Br	Br2, l	24.520	0.010
Kr	Kr, g	6.197
Xe	Xe, g	6.197

Data from CODATA
Cox, J.D.; Wagman, D.D.; Medvedev, V.A.CODATA Key Values for Thermodynamics. Hemisphere, New York, 1989

For gas-phase species with well defined enthalpies of formation that are useful in calculating reactions see section VII.C.2 Species with well-known enthalpies of formation

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