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

---

NIST policy on privacy, security, and accessibility.

---

© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to cccbdb@nist.gov.

IV.A.4. (XIV.F.)

Relative enthalpies of isomers - Comparison of 298.15K enthalpies (kJ mol^-1)

Isomers of C₆H₁₂O

index	Species	CAS number	Name	Relative experimental enthalpy (kJ mol-1)	sketch
a	C6H12O	592905	Oxepane
b	C6H12O	66251	hexanal	0.0

The calculated enthalpies include the calculated and scaled vibrational zero-point energy.

---

Methods with predefined basis sets

semi-empirical	AM1	171.7 a
	PM3	202.4 a
	PM6	170.8 a
composite	G1	NC
	G2MP2	NC
	G2	NC
	G3	NC
	G3B3	NC
	G4	NC
	CBS-Q	NC

---

Methods with standard basis sets

		6-311+G(3df,2p)
density functional	B97D3	0.0 b
		6-311+G(3df,2p)

---

Methods with effective core potentials (select basis sets)

		CEP-31G	CEP-31G*	CEP-121G	CEP-121G*	LANL2DZ	SDD	cc-pVTZ-PP	aug-cc-pVTZ-PP	Def2TZVPP
hartree fock	HF									0.0 b
density functional	B3LYP									0.0 b
	PBEPBE									0.0 b
Moller Plesset perturbation	MP2									0.0 b

NC = not calculated

---

For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.
gaw refers to the group additivity method implemeted in the NIST Chemistry Webbook.

See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.