Molecular formula
C21H26N2O4S
299 compounds have this formula on CompoundList.
- Molar mass
- 402.51g/mol
- Monoisotopic mass
- 402.1613Da
- Atoms
- 54
- Elements
- 5
- Rings plus double bonds
- 10
The formula C21H26N2O4S describes a molecule made of 21 carbon atoms, 26 hydrogen atoms, 2 nitrogen atoms, 4 oxygen atoms and 1 sulfur atom. It is written in Hill notation: carbon first, then hydrogen, then the other elements in alphabetical order. The formula tells you which atoms are present, not how they are connected, which is why several different chemicals can share it.
Elemental composition
- C Carbon × 2162.66%12.011 × 21 = 252.231 g/mol
- H Hydrogen × 266.51%1.008 × 26 = 26.208 g/mol
- N Nitrogen × 26.96%14.007 × 2 = 28.014 g/mol
- O Oxygen × 415.90%15.999 × 4 = 63.996 g/mol
- S Sulfur × 17.97%32.06 × 1 = 32.060 g/mol
Look up another formula
Compounds with the formula C21H26N2O4S
Isomers we list, best known first. Open one to see its structure, properties, safety data and suppliers.
Showing 101 to 200 of 299 compounds
![4-[(3,5-Dimethylpiperidin-1-yl)sulfonyl]-N-(3-methoxyphenyl)benzamide chemical structure, C21H26N2O4S, CAS 476308-51-7](/s/REHSXCBBWJTBGV-UHFFFAOYSA-N.svg)
4-[(3,5-Dimethylpiperidin-1-yl)sulfonyl]-N-(3-methoxyphenyl)benzamide
CAS 476308-51-7C21H26N2O4S
![Isobutyl 5-(4-ethoxyphenyl)-2,7-dimethyl-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate chemical structure, C21H26N2O4S, CAS 620554-51-0](/s/OOXACVZAZSYMFR-UHFFFAOYSA-N.svg)
Isobutyl 5-(4-ethoxyphenyl)-2,7-dimethyl-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate
CAS 620554-51-0C21H26N2O4S
![Isopropyl 2,7-dimethyl-3-oxo-5-(4-propoxyphenyl)-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate chemical structure, C21H26N2O4S, CAS 620551-57-7](/s/NBYSHNFCEIWNSZ-UHFFFAOYSA-N.svg)
Isopropyl 2,7-dimethyl-3-oxo-5-(4-propoxyphenyl)-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate
CAS 620551-57-7C21H26N2O4S
4-((3,5-Dimethylpiperidin-1-yl)sulfonyl)-N-(2-methoxyphenyl)benzamide
CAS 392324-05-9C21H26N2O4S
![Methyl 8-methyl-4-oxo-6-[4-(pentyloxy)phenyl]-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazine-7-carboxylate chemical structure, C21H26N2O4S, CAS 620553-51-7](/s/KMRCXDJHBNDOAA-UHFFFAOYSA-N.svg)
Methyl 8-methyl-4-oxo-6-[4-(pentyloxy)phenyl]-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazine-7-carboxylate
CAS 620553-51-7C21H26N2O4S
4-Butoxy-N-(5-(1,1-dioxidoisothiazolidin-2-yl)-2-methylphenyl)benzamide
CAS 946261-33-2C21H26N2O4S
4-Butoxy-N-(1-methylsulfonyl-3,4-dihydro-2H-quinolin-6-yl)benzamide
CAS 899988-82-0C21H26N2O4S
N-(2-((3,4-Dihydroisoquinolin-2(1H)-yl)sulfonyl)ethyl)-3-(4-methoxyphenyl)propanamide
CAS 922115-67-1C21H26N2O4S
(E)-3-(Furan-2-yl)-N-(2-(1-tosylpiperidin-2-yl)ethyl)acrylamide
CAS 1331424-51-1C21H26N2O4S
![N-{[1-(Furan-3-carbonyl)piperidin-4-yl]methyl}-5,6,7,8-tetrahydronaphthalene-2-sulfonamide chemical structure, C21H26N2O4S, CAS 1396850-46-6](/s/ZNYCRFWZNMPLNL-UHFFFAOYSA-N.svg)
N-{[1-(Furan-3-carbonyl)piperidin-4-yl]methyl}-5,6,7,8-tetrahydronaphthalene-2-sulfonamide
CAS 1396850-46-6C21H26N2O4S
3-(2,5-Dimethylphenylsulfonamido)cyclohexyl phenylcarbamate
CAS 1396686-93-3C21H26N2O4S
![2-[4-(Cyclohexylsulfamoyl)phenoxy]-N-(3-methylphenyl)acetamide chemical structure, C21H26N2O4S, CAS 664312-85-0](/s/UEGYNBQFHBFSDB-UHFFFAOYSA-N.svg)
2-[4-(Cyclohexylsulfamoyl)phenoxy]-N-(3-methylphenyl)acetamide
CAS 664312-85-0C21H26N2O4S
N-(2-Ethoxyphenyl)-1-(4-methylphenyl)sulfonylpiperidine-4-carboxamide
CAS 433697-53-1C21H26N2O4S
4-(Azepan-1-ylsulfonyl)-N-(4-ethoxyphenyl)benzamide
CAS 307326-30-3C21H26N2O4S
![N-[4-(Cyclohexylsulfamoyl)phenyl]-2-(2-methoxyphenyl)acetamide chemical structure, C21H26N2O4S, CAS 827617-48-1](/s/JPKIRFAGFPKTNR-UHFFFAOYSA-N.svg)
N-[4-(Cyclohexylsulfamoyl)phenyl]-2-(2-methoxyphenyl)acetamide
CAS 827617-48-1C21H26N2O4S
![2-{[(4-Methoxyphenyl)carbonyl]amino}-N-(3-methoxypropyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide chemical structure, C21H26N2O4S, CAS 608493-48-7](/s/LACFXBALGXROAP-UHFFFAOYSA-N.svg)
2-{[(4-Methoxyphenyl)carbonyl]amino}-N-(3-methoxypropyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide
CAS 608493-48-7C21H26N2O4S
![4-[Cyclohexyl(methyl)sulfamoyl]-N-(2-methoxyphenyl)benzamide chemical structure, C21H26N2O4S, CAS 683791-89-1](/s/LBCLRHDSSWOBMD-UHFFFAOYSA-N.svg)
4-[Cyclohexyl(methyl)sulfamoyl]-N-(2-methoxyphenyl)benzamide
CAS 683791-89-1C21H26N2O4S
![Methyl 2,7-dimethyl-3-oxo-5-[4-(pentyloxy)phenyl]-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate chemical structure, C21H26N2O4S, CAS 620553-95-9](/s/WNMAGJFFCAXKIB-UHFFFAOYSA-N.svg)
Methyl 2,7-dimethyl-3-oxo-5-[4-(pentyloxy)phenyl]-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate
CAS 620553-95-9C21H26N2O4S
![(E)-N-[5-(Diethylsulfamoyl)-2-methoxyphenyl]-2-methyl-3-phenylprop-2-enamide chemical structure, C21H26N2O4S, CAS 587845-75-8](/s/PUYWNIGHOORTSA-JQIJEIRASA-N.svg)
(E)-N-[5-(Diethylsulfamoyl)-2-methoxyphenyl]-2-methyl-3-phenylprop-2-enamide
CAS 587845-75-8C21H26N2O4S
![4-tert-Butyl-N-[5-(1,1-dioxo-1,2-thiazolidin-2-yl)-2-methoxyphenyl]benzamide chemical structure, C21H26N2O4S, CAS 1005297-14-2](/s/KGYJXVHVIBXTNJ-UHFFFAOYSA-N.svg)
4-tert-Butyl-N-[5-(1,1-dioxo-1,2-thiazolidin-2-yl)-2-methoxyphenyl]benzamide
CAS 1005297-14-2C21H26N2O4S
5-Ethyl-2-methoxy-N-(2-(5-methoxy-2-methyl-1H-indol-3-yl)ethyl)benzenesulfonamide
CAS 927637-73-8C21H26N2O4S
N-(2-(2,5-Dimethyl-1H-indol-3-yl)ethyl)-2,5-dimethoxy-4-methylbenzenesulfonamide
CAS 927637-79-4C21H26N2O4S
2-(1-((4-Methoxyphenyl)sulfonyl)piperidin-2-yl)-N-(p-tolyl)acetamide
CAS 941911-15-5C21H26N2O4S
![4-Ethoxy-N-[1-(2-methylpropyl)-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl]benzene-1-sulfonamide chemical structure, C21H26N2O4S, CAS 941955-52-8](/s/PZUFJNVJHOGKLI-UHFFFAOYSA-N.svg)
4-Ethoxy-N-[1-(2-methylpropyl)-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl]benzene-1-sulfonamide
CAS 941955-52-8C21H26N2O4S
- 4-Ethoxy-N-((1-tosylpyrrolidin-2-yl)methyl)benzamide887862-30-8C21H26N2O4S
- N-(2-(Propylsulfonyl)-1,2,3,4-tetrahydroisoquinolin-7-yl)-2-(p-tolyloxy)acetamide954591-65-2C21H26N2O4S
- 2-(2-Methylphenoxy)-N-[3-(1,2,3,4-tetrahydroisoquinoline-2-sulfonyl)propyl]acetamide1040642-18-9C21H26N2O4S
- 4-Propyl-N-(3,3,5-trimethyl-4-oxo-2,3,4,5-tetrahydrobenzo[b][1,4]oxazepin-8-yl)benzenesulfonamide922096-88-6C21H26N2O4S
- N-(5-Isobutyl-3,3-dimethyl-4-oxo-2,3,4,5-tetrahydrobenzo[b][1,4]oxazepin-8-yl)benzenesulfonamide922124-75-2C21H26N2O4S
- N-(2-(Indolin-1-ylsulfonyl)ethyl)-2-(4-isopropylphenoxy)acetamide922053-05-2C21H26N2O4S
- 4-Ethoxy-3-methyl-N-(1-propionyl-1,2,3,4-tetrahydroquinolin-6-yl)benzenesulfonamide946211-37-6C21H26N2O4S
- N-(2-(2,4-Dioxothiazolidin-3-yl)cyclohexyl)-4-phenyltetrahydro-2H-pyran-4-carboxamide1207038-83-2C21H26N2O4S
- Methyl 5-(2-methylpropyl)-2-{[(4-phenyltetrahydro-2H-pyran-4-yl)carbonyl]amino}-1,3-thiazole-4-carboxylate1574474-31-9C21H26N2O4S
- 2-(2-Isopropylphenoxy)-N-[4-(1-pyrrolidinylsulfonyl)phenyl]acetamide606923-52-8C21H26N2O4S
- 2-(4-Isopropylphenoxy)-N-[4-(1-pyrrolidinylsulfonyl)phenyl]acetamide651018-68-7C21H26N2O4S
- 1-(Benzo[d][1,3]dioxol-5-ylmethyl)-4-((2,3,4-trimethylphenyl)sulfonyl)piperazine694516-77-3C21H26N2O4S
- N-(2,3-Dimethylphenyl)-4-methyl-N-(2-morpholin-4-yl-2-oxoethyl)benzenesulfonamide532421-42-4C21H26N2O4S
- N-[4-(Azepan-1-ylsulfonyl)phenyl]-2-methoxy-2-phenylacetamide708220-45-5C21H26N2O4S
- N-(4-{[Cyclohexyl(methyl)amino]sulfonyl}phenyl)-2-methoxybenzamide717861-07-9C21H26N2O4S
- 2-Methylpropyl 2-ethyl-5-(4-methoxyphenyl)-7-methyl-3-oxo-2H,3H,5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate620553-62-0C21H26N2O4S
- Ethyl 6-(4-butoxyphenyl)-8-methyl-4-oxo-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazine-7-carboxylate616214-07-4C21H26N2O4S
- Methyl 5-(4-butoxyphenyl)-2-ethyl-7-methyl-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate836651-43-5C21H26N2O4S
- 4-[Cyclohexyl(methyl)sulfamoyl]-N-(4-methoxyphenyl)benzamide683761-54-8C21H26N2O4S
- 4-Butoxy-N-[4-(1,1-dioxothiazinan-2-yl)phenyl]benzamide899979-92-1C21H26N2O4S
- 2-Methoxy-4,5-dimethyl-N-(3-methyl-4-(2-oxopiperidin-1-yl)phenyl)benzenesulfonamide941873-78-5C21H26N2O4S
- N-(2,3-Dimethylphenyl)-3-(4-morpholin-4-ylsulfonylphenyl)propanamide932146-70-8C21H26N2O4S
- 4-[3-(Morpholin-4-yl)-3-oxopropyl]-N-(1-phenylethyl)benzenesulfonamide878972-54-4C21H26N2O4S
- N-Benzyl-2-(1-((4-methoxyphenyl)sulfonyl)piperidin-2-yl)acetamide941955-92-6C21H26N2O4S
- N-(1-Ethyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-4-isobutoxybenzenesulfonamide922080-05-5C21H26N2O4S
- N-[1-(2,2-Dimethylpropanoyl)-2,3-dihydro-1H-indol-6-yl]-2-methoxy-5-methylbenzene-1-sulfonamide1040659-81-1C21H26N2O4S
- N-(3-((3,4-Dihydroisoquinolin-2(1H)-yl)sulfonyl)propyl)-4-ethoxybenzamide1040641-75-5C21H26N2O4S
- N-[1-(4-Methoxybenzenesulfonyl)-1,2,3,4-tetrahydroquinolin-6-yl]-2,2-dimethylpropanamide946212-68-6C21H26N2O4S
- {1-[({[2-(4-Methoxyphenyl)-1,3-thiazol-4-yl]acetyl}amino)methyl]cyclohexyl}acetic acid1144430-85-2C21H26N2O4S
- {1-[({[2-(3-Methoxyphenyl)-1,3-thiazol-4-yl]acetyl}amino)methyl]cyclohexyl}acetic acid1190274-94-2C21H26N2O4S
- 2-Benzyl-1-(2,5-diethoxy-4-methylbenzenesulfonyl)-4,5-dihydro-1H-imidazole1206122-13-5C21H26N2O4S
- N-(4-(N-((2-Hydroxy-1,2,3,4-tetrahydronaphthalen-2-yl)methyl)sulfamoyl)phenyl)isobutyramide1421457-32-0C21H26N2O4S
- N-(2,3-Dimethylphenyl)-1-(4-methoxyphenyl)sulfonylpiperidine-4-carboxamide510722-47-1C21H26N2O4S
- N-(3-Methoxyphenyl)-N-[2-(4-methylpiperidin-1-yl)-2-oxoethyl]benzenesulfonamide426224-46-6C21H26N2O4S
- N-(3-Acetylphenyl)-3-[4-(tert-butylsulfamoyl)phenyl]propanamide701932-58-3C21H26N2O4S
- Ethyl 4-(3,4-dimethylphenyl)-2-[(morpholin-4-ylacetyl)amino]thiophene-3-carboxylate379242-63-4C21H26N2O4S
- N-[4-(Dimethylamino)benzyl]-N-(1,1-dioxidotetrahydrothiophen-3-yl)-2-methoxybenzamide587004-97-5C21H26N2O4S
- N-(1-Isobutyryl-1,2,3,4-tetrahydroquinolin-6-yl)-4-methoxy-3-methylbenzenesulfonamide946258-46-4C21H26N2O4S
- N-(1-Isobutyryl-1,2,3,4-tetrahydroquinolin-6-yl)-2-methoxy-5-methylbenzenesulfonamide946333-81-9C21H26N2O4S
- 4-Ethoxy-N-(1-isobutyryl-1,2,3,4-tetrahydroquinolin-6-yl)benzenesulfonamide946380-59-2C21H26N2O4S
- N-(1-Isobutyryl-1,2,3,4-tetrahydroquinolin-7-yl)-4-methoxy-3-methylbenzenesulfonamide1005298-79-2C21H26N2O4S
- N-(1-Isobutyryl-1,2,3,4-tetrahydroquinolin-7-yl)-2-methoxy-5-methylbenzenesulfonamide1005300-91-3C21H26N2O4S
- 4-Ethoxy-N-(1-isobutyryl-1,2,3,4-tetrahydroquinolin-7-yl)benzenesulfonamide1026290-91-4C21H26N2O4S
- Ethyl (2-(4-(tert-butyl)benzamido)-4,5-dimethylthiophene-3-carbonyl)carbamate896316-76-0C21H26N2O4S
- 2-Methoxy-4,5-dimethyl-N-(4-methyl-3-(2-oxopiperidin-1-yl)phenyl)benzenesulfonamide941945-32-0C21H26N2O4S
- N-[4-(Benzyloxy)phenyl]-1-(ethylsulfonyl)piperidine-4-carboxamide915927-52-5C21H26N2O4S
- N-(2-Methoxyphenyl)-2-(1-tosylpiperidin-2-yl)acetamide941955-44-8C21H26N2O4S
- 2-[1-(4-Methoxybenzenesulfonyl)piperidin-2-yl]-N-(3-methylphenyl)acetamide941956-03-2C21H26N2O4S
- 2-(1-((4-Methoxyphenyl)sulfonyl)piperidin-2-yl)-N-(o-tolyl)acetamide941991-30-6C21H26N2O4S
- 4-Ethoxy-N-(1-ethyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-3,5-dimethylbenzenesulfonamide922080-08-8C21H26N2O4S
- 2-(4-Ethoxyphenyl)-N-[2-(1,2,3,4-tetrahydroisoquinoline-2-sulfonyl)ethyl]acetamide922115-41-1C21H26N2O4S
- 2-Methoxy-4,5-dimethyl-N-(2-oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)benzenesulfonamide941906-30-5C21H26N2O4S
- 4-Methoxy-3,5-dimethyl-N-(2-oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)benzene-1-sulfonamide946372-53-8C21H26N2O4S
- 5-Ethyl-2-methoxy-N-(2-oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)benzenesulfonamide941954-81-0C21H26N2O4S
- N-(1-Butyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-4-methoxy-3-methylbenzenesulfonamide941955-10-8C21H26N2O4S
- N-(1-Butyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-4-ethoxybenzenesulfonamide941906-47-4C21H26N2O4S
- N-(1-Butyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-4-methoxy-2-methylbenzenesulfonamide955606-25-4C21H26N2O4S
- N-(1-Isobutyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-4-methoxy-3-methylbenzenesulfonamide942003-05-6C21H26N2O4S
- N-(1-Isobutyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-2-methoxy-5-methylbenzenesulfonamide941912-37-4C21H26N2O4S
- 4-Methoxy-N-[1-(3-methylbutyl)-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl]benzene-1-sulfonamide941955-82-4C21H26N2O4S
- N-((1-Benzylpiperidin-4-yl)methyl)-2,3-dihydrobenzo[b][1,4]dioxine-6-sulfonamide953260-82-7C21H26N2O4S
- 4-Isopropyl-N-(2-oxo-2-(2-phenylmorpholino)ethyl)benzenesulfonamide954095-53-5C21H26N2O4S
- N-((1-(4-Methoxyphenyl)-5-oxopyrrolidin-3-yl)methyl)-2,4,6-trimethylbenzenesulfonamide954655-38-0C21H26N2O4S
- N-((1-(4-Ethoxyphenyl)-5-oxopyrrolidin-3-yl)methyl)-3,4-dimethylbenzenesulfonamide955255-57-9C21H26N2O4S
- N-((1-(4-Ethoxyphenyl)-5-oxopyrrolidin-3-yl)methyl)-2,4-dimethylbenzenesulfonamide954607-82-0C21H26N2O4S
- N-((1-(4-Ethoxyphenyl)-5-oxopyrrolidin-3-yl)methyl)-2,5-dimethylbenzenesulfonamide954656-00-9C21H26N2O4S
- 2-Ethoxy-5-methyl-N-(2-oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)benzenesulfonamide946270-20-8C21H26N2O4S
- 4-Ethoxy-3-methyl-N-(2-oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)benzenesulfonamide946325-76-4C21H26N2O4S
- N-(2-Oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)-4-propoxybenzenesulfonamide946325-80-0C21H26N2O4S
- 2-(4-Methoxyphenyl)-N-(2-oxo-1-propyl-1,2,3,4-tetrahydroquinolin-6-yl)ethanesulfonamide954614-26-7C21H26N2O4S
- N-(1-Butyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-2-methoxy-5-methylbenzenesulfonamide946221-80-3C21H26N2O4S
- N-(2-(Propylsulfonyl)-1,2,3,4-tetrahydroisoquinolin-7-yl)-2-(m-tolyloxy)acetamide954709-39-8C21H26N2O4S
- 2-(4-Methoxyphenyl)-N-(2-propionyl-1,2,3,4-tetrahydroisoquinolin-7-yl)ethanesulfonamide955752-42-8C21H26N2O4S
- 4-Methoxy-N-(2-phenylethyl)-3-(piperidin-1-ylsulfonyl)benzamide931875-14-8C21H26N2O4S
- N-Cyclopentyl-4-methoxy-3-[(2-phenylethyl)sulfamoyl]benzamide954282-95-2C21H26N2O4S
- 2,3,4,5,6-Pentamethyl-N-(4-methyl-5-oxo-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepin-7-yl)benzenesulfonamide922006-81-3C21H26N2O4S
Frequently asked questions
What is the molar mass of C21H26N2O4S?
The molar mass of C21H26N2O4S is 402.51 g/mol, calculated from standard atomic weights for 21 carbon atoms, 26 hydrogen atoms, 2 nitrogen atoms, 4 oxygen atoms and 1 sulfur atom. The monoisotopic mass is 402.1613 Da.
How many compounds have the formula C21H26N2O4S?
CompoundList lists 299 compounds with the molecular formula C21H26N2O4S, including 4-[(3,5-Dimethylpiperidin-1-yl)sulfonyl]-N-(3-methoxyphenyl)benzamide, Isobutyl 5-(4-ethoxyphenyl)-2,7-dimethyl-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate, Isopropyl 2,7-dimethyl-3-oxo-5-(4-propoxyphenyl)-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate. Compounds that share a formula are isomers. They contain the same atoms arranged differently, so their properties, uses and prices can be very different.
What is the degree of unsaturation of C21H26N2O4S?
C21H26N2O4S has a degree of unsaturation of 10. That is the total number of rings and pi bonds (a double bond counts as one, a triple bond as two) in any structure with this formula.