List of isomers of alkanes

A focused list of alkane structural isomers with formulas, names, SMILES, and source identifiers.

Name	Formula	MW (g/mol)	Category	SMILES	PubChem CID
Methane	CH4	16.04	C1 alkane	`C`	297
Ethane	C2H6	30.07	C2 alkane	`CC`	6324
Propane	C3H8	44.10	C3 alkane	`CCC`	6334
n-Butane	C4H10	58.12	C4 alkane isomer	`CCCC`	7843
Isobutane	C4H10	58.12	C4 alkane isomer	`CC(C)C`	6360
n-Pentane	C5H12	72.15	C5 alkane isomer	`CCCCC`	8003
Isopentane	C5H12	72.15	C5 alkane isomer	`CCC(C)C`	6556
Neopentane	C5H12	72.15	C5 alkane isomer	`CC(C)(C)C`	10041
n-Hexane	C6H14	86.18	C6 alkane isomer	`CCCCCC`	8058
2-Methylpentane	C6H14	86.18	C6 alkane isomer	`CCCC(C)C`	7892
3-Methylpentane	C6H14	86.18	C6 alkane isomer	`CCC(C)CC`	7282
2,2-Dimethylbutane	C6H14	86.18	C6 alkane isomer	`CCC(C)(C)C`	6403
2,3-Dimethylbutane	C6H14	86.18	C6 alkane isomer	`CC(C)C(C)C`	6589
n-Heptane	C7H16	100.21	C7 alkane isomer	`CCCCCCC`	8900
2-Methylhexane	C7H16	100.21	C7 alkane isomer	`CCCCC(C)C`	11582
3-Methylhexane	C7H16	100.21	C7 alkane isomer	`CCCC(C)CC`	11507
3-Ethylpentane	C7H16	100.21	C7 alkane isomer	`CCC(CC)CC`	12048
2,2-Dimethylpentane	C7H16	100.21	C7 alkane isomer	`CCCC(C)(C)C`	11542
2,3-Dimethylpentane	C7H16	100.21	C7 alkane isomer	`CCC(C)C(C)C`	11260
2,4-Dimethylpentane	C7H16	100.21	C7 alkane isomer	`CC(C)CC(C)C`	7907
3,3-Dimethylpentane	C7H16	100.21	C7 alkane isomer	`CCC(C)(C)CC`	11229
2,2,3-Trimethylbutane	C7H16	100.21	C7 alkane isomer	`CC(C)C(C)(C)C`	10044
n-Octane	C8H18	114.23	C8 alkane isomer	`CCCCCCCC`	356
2-Methylheptane	C8H18	114.23	C8 alkane isomer	`CCCCCC(C)C`	11594
3-Methylheptane	C8H18	114.23	C8 alkane isomer	`CCCCC(C)CC`	11519
4-Methylheptane	C8H18	114.23	C8 alkane isomer	`CCCC(C)CCC`	11512
3-Ethylhexane	C8H18	114.23	C8 alkane isomer	`CCCC(CC)CC`	12096
2,2-Dimethylhexane	C8H18	114.23	C8 alkane isomer	`CCCCC(C)(C)C`	11551
2,3-Dimethylhexane	C8H18	114.23	C8 alkane isomer	`CCCC(C)C(C)C`	11447
2,4-Dimethylhexane	C8H18	114.23	C8 alkane isomer	`CCC(C)CC(C)C`	11511
2,5-Dimethylhexane	C8H18	114.23	C8 alkane isomer	`CC(C)CCC(C)C`	11592
3,3-Dimethylhexane	C8H18	114.23	C8 alkane isomer	`CCCC(C)(C)CC`	11233
3,4-Dimethylhexane	C8H18	114.23	C8 alkane isomer	`CCC(C)C(C)CC`	11412
Nonane	C9H20	128.26	Linear alkane	`CCCCCCCCC`	8141
Decane	C10H22	142.29	Linear alkane	`CCCCCCCCCC`	15600
Undecane	C11H24	156.31	Linear alkane	`CCCCCCCCCCC`	14257
Dodecane	C12H26	170.34	Linear alkane	`CCCCCCCCCCCC`	8182
Tridecane	C13H28	184.37	Linear alkane	`CCCCCCCCCCCCC`	12388
Tetradecane	C14H30	198.39	Linear alkane	`CCCCCCCCCCCCCC`	12389
Pentadecane	C15H32	212.42	Linear alkane	`CCCCCCCCCCCCCCC`	12391
Hexadecane	C16H34	226.45	Linear alkane	`CCCCCCCCCCCCCCCC`	11006
Heptadecane	C17H36	240.47	Linear alkane	`CCCCCCCCCCCCCCCCC`	12398
Octadecane	C18H38	254.50	Linear alkane	`CCCCCCCCCCCCCCCCCC`	11635
Nonadecane	C19H40	268.53	Linear alkane	`CCCCCCCCCCCCCCCCCCC`	12401
Eicosane	C20H42	282.56	Linear alkane	`CCCCCCCCCCCCCCCCCCCC`	8222
2-Methyloctane	C9H20	128.26	Methylalkane isomer	`CCCCCCC(C)C`	18591
3-Methyloctane	C9H20	128.26	Methylalkane isomer	`CCCCCC(C)CC`	16664
4-Methyloctane	C9H20	128.26	Methylalkane isomer	`CCCCC(C)CCC`	16665
2-Methylnonane	C10H22	142.29	Methylalkane isomer	`CCCCCCCC(C)C`	13379
3-Methylnonane	C10H22	142.29	Methylalkane isomer	`CCCCCCC(C)CC`	22202
4-Methylnonane	C10H22	142.29	Methylalkane isomer	`CCCCCC(C)CCC`	28455
5-Methylnonane	C10H22	142.29	Methylalkane isomer	`CCCCC(C)CCCC`	27518
2-Methyldecane	C11H24	156.31	Methylalkane isomer	`CCCCCCCCC(C)C`	23415
3-Methyldecane	C11H24	156.31	Methylalkane isomer	`CCCCCCCC(C)CC`	92239
4-Methyldecane	C11H24	156.31	Methylalkane isomer	`CCCCCCC(C)CCC`	17835
5-Methyldecane	C11H24	156.31	Methylalkane isomer	`CCCCCC(C)CCCC`	93071
2-Methylundecane	C12H26	170.34	Methylalkane isomer	`CCCCCCCCCC(C)C`	23459
3-Methylundecane	C12H26	170.34	Methylalkane isomer	`CCCCCCCCC(C)CC`	13845
4-Methylundecane	C12H26	170.34	Methylalkane isomer	`CCCCCCCC(C)CCC`	520454
5-Methylundecane	C12H26	170.34	Methylalkane isomer	`CCCCCCC(C)CCCC`	94213
2-Methyldodecane	C13H28	184.37	Methylalkane isomer	`CCCCCCCCCCC(C)C`	15270
3-Methyldodecane	C13H28	184.37	Methylalkane isomer	`CCCCCCCCCC(C)CC`	28469
4-Methyldodecane	C13H28	184.37	Methylalkane isomer	`CCCCCCCCC(C)CCC`	521958
5-Methyldodecane	C13H28	184.37	Methylalkane isomer	`CCCCCCCC(C)CCCC`	519423
2-Methyltridecane	C14H30	198.39	Methylalkane isomer	`CCCCCCCCCCCC(C)C`	15269
3-Methyltridecane	C14H30	198.39	Methylalkane isomer	`CCCCCCCCCCC(C)CC`	110848
4-Methyltridecane	C14H30	198.39	Methylalkane isomer	`CCCCCCCCCC(C)CCC`	117325
5-Methyltridecane	C14H30	198.39	Methylalkane isomer	`CCCCCCCCC(C)CCCC`	520182
2-Methyltetradecane	C15H32	212.42	Methylalkane isomer	`CCCCCCCCCCCCC(C)C`	15268
3-Methyltetradecane	C15H32	212.42	Methylalkane isomer	`CCCCCCCCCCCC(C)CC`	86735
4-Methyltetradecane	C15H32	212.42	Methylalkane isomer	`CCCCCCCCCCC(C)CCC`	520179
5-Methyltetradecane	C15H32	212.42	Methylalkane isomer	`CCCCCCCCCC(C)CCCC`	98976
2-Methylpentadecane	C16H34	226.45	Methylalkane isomer	`CCCCCCCCCCCCCC(C)C`	15267
3-Methylpentadecane	C16H34	226.45	Methylalkane isomer	`CCCCCCCCCCCCC(C)CC`	17899
4-Methylpentadecane	C16H34	226.45	Methylalkane isomer	`CCCCCCCCCCCC(C)CCC`	17751
5-Methylpentadecane	C16H34	226.45	Methylalkane isomer	`CCCCCCCCCCC(C)CCCC`	32796
2,2-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCCCCC(C)(C)C`	14062
2,3-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCCCC(C)C(C)C`	26375
2,4-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCCC(C)CC(C)C`	16656
2,5-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCC(C)CCC(C)C`	16662
3,3-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCCCC(C)(C)CC`	520991
3,4-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCCC(C)C(C)CC`	13534
3,5-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCC(C)CC(C)CC`	13558
4,4-Dimethylheptane	C9H20	128.26	Dimethylalkane isomer	`CCCC(C)(C)CCC`	136827
2,2-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCCCCC(C)(C)C`	85150
2,3-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCCCC(C)C(C)C`	23531
2,4-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCCC(C)CC(C)C`	92978
2,5-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCC(C)CCC(C)C`	139988
3,3-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCCCC(C)(C)CC`	138117
3,4-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCCC(C)C(C)CC`	85926
3,5-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCC(C)CC(C)CC`	139989
4,4-Dimethyloctane	C10H22	142.29	Dimethylalkane isomer	`CCCCC(C)(C)CCC`	85151
2,2-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCCCCC(C)(C)C`	176691
2,3-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCCCC(C)C(C)C`	520397
2,4-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCCC(C)CC(C)C`	524749
2,5-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCC(C)CCC(C)C`	28456
3,3-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCCCC(C)(C)CC`	529413
3,4-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCCC(C)C(C)CC`	13353494
3,5-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCC(C)CC(C)CC`	20143700
4,4-Dimethylnonane	C11H24	156.31	Dimethylalkane isomer	`CCCCCC(C)(C)CCC`	53425988

Page 1 of 2

per page

Methodology

The starter list covers low-carbon alkanes and named structural isomers. PubChem identifiers anchor each molecule, while RDKit or Open Babel can canonicalize larger generated isomer sets.

Sources

PubChem

Canonical compound identifiers, names, formulas, structures, SMILES, and downloadable compound records.

NIST Chemistry WebBook

Reference physical chemistry data and diatomic constants for selected species.

RDKit

Derived descriptors such as molecular weight, LogP, TPSA, hydrogen-bond counts, and canonicalized structures.

Related datasets

Small-molecule drugs Biological molecules Organic compounds Common molecules