Building Blocks
The grammar of organic chemistry
Every drug, polymer, perfume, and pesticide is assembled from a tiny vocabulary of bonds and functional groups. The C-H bond, the carbonyl, the aromatic ring, the alcohol, the ester — these recur in everything from methane to morphine. This collection covers the small molecules organic chemists call "starting materials" and "building blocks": alkanes, alkenes, aromatics, alcohols, ketones, amines. Not glamorous individually, but understanding them is how you stop seeing molecules as random shapes and start seeing them as sentences. Worth the time even if you'll never run a reaction yourself.
Featured
Stories in this theme
All 262 molecules in this theme
Urea
Wöhler's organic synthesis milestone; fertilizer
Polyethylene (repeat)
PE; world's most produced plastic
Acetic acid
Vinegar; archetypal weak acid
Polystyrene (repeat)
PS; foam + packaging
1-Bromopropane
Primary alkyl halide; SN2 substrate
1-Butanol
Biofuel candidate; lacquer solvent
1-Butene
Polymer comonomer
1-Butyne
Terminal alkyne
1-Hexene
LLDPE comonomer
1-Pentanol
Amyl alcohol; flavor solvent
1-Pentene
Terminal alkene; LDPE comonomer
1-Propanol
Primary alcohol solvent
1,2,3-Triazole
Click chemistry product (CuAAC)
1,3-Butadiene
Synthetic rubber monomer; conjugated diene
1,3,5-Triazine
Melamine + cyanuric acid core
1,4-Dioxane
Cyclic diether solvent
2-Bromopropane
Secondary alkyl halide; SN1/E1 substrate
2-Butyne
Internal alkyne
2-Methylpentane
Branched C6 isomer
2,2-Dimethylbutane
Branched C6; gasoline component
2,3-Pentanedione
Buttery flavor; alpha-diketone
3-Methylpentane
Branched C6 isomer
4-Methyl-2-pentanone (MIBK)
MIBK solvent
5-Hydroxymethylfurfural (HMF)
Biomass platform chemical
Acenaphthylene
PAH with cyclopenta ring
Acetaldehyde
Ethanol metabolite; toxic intermediate
Acetamide
Primary amide; plasticizer
Acetic anhydride
Acetylation reagent; aspirin synthesis
Acetone
Simplest ketone; common solvent; nail polish remover
Acetonitrile
Polar aprotic solvent; HPLC mobile phase
Acetophenone
Aryl methyl ketone; Friedel-Crafts product
Acetylacetone
1,3-diketone; enol tautomer demo; acac ligand
Acetylene
Welding gas; sp-hybridized; weak acid
Acridine
DNA intercalator; dye
Acrolein
Burnt-fat odor; toxic α,β-unsaturated
Acrylic acid
Acrylate polymers; super-absorbents
Acrylonitrile
PAN polymer; Michael acceptor
Adamantane
Cage structure; diamond unit cell motif
Adipic acid
Nylon-6,6 monomer
Adiponitrile
Hexamethylenediamine precursor
Aniline
Aryl amine; dye industry foundation
Anisole
Methoxybenzene; activated aromatic
Anthracene
Linear tricyclic PAH; fluorescent dye
Aziridine
3-ring amine; alkylating warhead
Benzaldehyde
Almond aroma; aldol substrate
Benzimidazole
Drug scaffold; PPI precursor
Benzo[a]pyrene
Tobacco-smoke carcinogen; DNA adduct former
Benzofuran
Fused O-heterocycle
Benzoic acid
Preservative E210; melting-point standard
Benzonitrile
Aromatic nitrile; coordinative solvent
Benzophenone
UV blocker; photochemistry sensitizer
Benzothiazole
Rubber vulcanization accelerator core
Benzothiophene
Fused S-heterocycle; coal-tar
Benzoxazole
Fused O+N scaffold
Benzyl alcohol
Preservative; solvent; fragrance
Benzyl cation
Resonance-stabilized benzylic cation
Benzyl chloride
Benzyl-cation stabilized; SN1/SN2 dual
Benzylamine
Primary benzylic amine
Biphenyl
PCB scaffold; heat transfer fluid
Bromobenzene
Aryl Grignard precursor
Bromomethane
Methylating agent; fumigant
Butane
Lighter fluid; LPG component
Butyl acetate
Fruity solvent; coatings
Butyraldehyde
Butanal; perfumery
Butyric acid
Rancid butter odor; gut microbiome
Camphor
Bicyclic terpenoid ketone; topical balm
Caproic acid
Hexanoic acid; goaty odor
Carbazole
OLED hole-transport material
Carbon tetrachloride
Banned ozone-depleter; radical initiator solvent
Carvacrol
Oregano oil; antimicrobial
Carvone
Spearmint/caraway enantiomers
Catechol
1,2-dihydroxybenzene; redox-active
Chlorobenzene
Aryl halide; SNAr substrate
Chloroethane
Ethylating agent; topical anesthetic
Chloromethane
Methylating agent; refrigerant
Chrysene
PAH; coal-tar component
Cinnamaldehyde
Cinnamon flavor
cis-2-Butene
cis isomer; geometric isomerism demo
Citric acid
Citrus acid; TCA cycle namesake
Corannulene
Bowl-shaped PAH; buckybowl
Coronene
Hexagonal PAH; graphene fragment
Cubane
Cubic carbon framework; high strain
Cyanuric acid
Pool sanitizer stabilizer
Cyclobutane
Strained 4-ring; puckered conformation
Cyclohexane
Chair/boat conformation classic; non-polar solvent
Cyclohexanol
Nylon-6 precursor; ring-puckering demo
Cyclohexanone
Nylon precursor; lab solvent
Cyclohexene
Diels-Alder substrate; bromination demo
Cyclopentadiene
Diels-Alder diene; Cp- ligand precursor
Cyclopentane
Envelope conformation; near-strainless
Cyclopropane
Highly strained; banana bonds; former anesthetic
DCC
Peptide-coupling dehydrating agent
Decalin
cis/trans-fused bicyclic; conformational analysis
Decane
Kerosene component
DIBAL-H
Partial-reduction of esters to aldehydes
Dichlorodifluoromethane (Freon-12)
Banned CFC refrigerant
Dichloromethane
DCM; common extraction solvent
Diethyl malonate
Malonic ester synthesis; alpha-anion source
Diethylamine
Secondary amine; rubber chemicals
Diisopropyl ether
Peroxide-prone ether solvent
Dimedone
5,5-dimethyl-1,3-cyclohexanedione; aldehyde test
Dimethyl carbonate
Green methylating agent
Dimethylamine
Secondary amine; rubber accelerator
DIPEA (Hünig's base)
Bulky non-nucleophilic base
Diphenylamine
Antioxidant; OLED material
DMAc
Polar aprotic solvent
DMF
Common polar aprotic solvent
Dodecane
Diesel surrogate; jet fuel component
EDC·HCl
Water-soluble peptide coupling reagent
Erythritol
Sugar alcohol sweetener
Ethane
Two-carbon alkane; natural gas component
Ethanol
Beverage alcohol; fuel; solvent
Ethanolamine
Phospholipid head group; CO2 scrubber
Ethyl acetate
Fruity solvent; nail polish
Ethyl formate
Rum/raspberry flavor
Ethylamine
Primary amine; drug precursor
Ethylbenzene
Styrene precursor
Ethylene
Plant hormone; polyethylene monomer
Ethylene glycol
Antifreeze; PET precursor
Ethylene oxide
Epoxide reagent; sterilant
Ethylenediamine
Bidentate ligand; EDTA precursor
Fluoranthene
PAH; benzopyrene metabolic context
Fluorene
OLED material scaffold; acidic CH
Formamide
Simplest amide; polar solvent
Formic acid
Simplest carboxylic acid; ant venom
Fumaric acid
trans-butenedioic; TCA cycle
Furan
5-ring aromatic O-heterocycle
Furfural
From pentose dehydration; bio-refinery feedstock
Glutaric acid
C5 dicarboxylic; nylon precursor
Glycerol
Triol; humectant; lipid backbone
Glycolic acid
Alpha-hydroxy acid; skincare
Glyoxal
Dialdehyde; crosslinker
Grubbs II
Olefin metathesis catalyst
Heptane
Octane-rating zero reference
Hexadecane (cetane)
Cetane number reference
Hexamethylbenzene
Fully substituted benzene; X-ray reference
Hexamethylenediamine
Nylon-6,6 monomer
Hexane
Common organic solvent; oil extraction
Hydrogen cyanide
Highly toxic; gold cyanidation
Hydroquinone
1,4-dihydroxybenzene; photo developer; skin lightener
Imidazole
His side chain; histamine; ionic liquid base
Indene
Indenyl ligand precursor; coal-tar fraction
Indole
Tryptophan + serotonin + IAA core
Iodobenzene
Cross-coupling substrate
Iodomethane
SN2 substrate textbook; methylating reagent
Isobutane
Branched C4; refrigerant
Isobutanol
Fermentation byproduct
Isobutylene
Butyl rubber monomer
Isobutyraldehyde
Branched C4 aldehyde
Isooctane (2,2,4-trimethylpentane)
Octane-rating 100 reference
Isopentane
Branched C5; ultra-low-T cryogen
Isophorone
α,β-unsaturated cyclic ketone
Isoprene
Natural rubber monomer; terpene unit
Isopropanol
Rubbing alcohol; lab solvent
Isoquinoline
Alkaloid scaffold (papaverine)
Isoxazole
1,2-positioned O+N; drug scaffold
Jacobsen catalyst
Asymmetric epoxidation
Lactic acid
Muscle fatigue; fermentation; PLA monomer
LDA
Hindered non-nucleophilic base
LiAlH4 (LAH)
Strong hydride reductant
m-Xylene
meta-dimethylbenzene; isophthalic acid feedstock
Maleic acid
cis-butenedioic; resin monomer
Maleic anhydride
Diels-Alder dienophile; resin monomer
Malic acid
Sour apples; TCA cycle
Malonic acid
Malonate ester synthesis backbone
Mannitol
Sugar alcohol; osmotic diuretic
Melamine
Plastic resin; protein-adulterant scandal
MeMgBr
Grignard methyl source
Mesitylene
1,3,5-trimethylbenzene
Methacrylic acid
PMMA precursor
Methane
Simplest alkane; natural gas main component
Methanol
Simplest alcohol; toxic; antifreeze; fuel
Methyl acetate
Pleasant odor solvent
Methyl ethyl ketone (MEK)
Industrial solvent; lacquer
Methyl salicylate
Wintergreen oil; topical analgesic
Methyl tert-butyl ether (MTBE)
Gasoline oxygenate; extraction solvent
Methyl vinyl ketone (MVK)
Michael acceptor textbook
Methylamine
Simplest primary amine; fishy odor
Methylcyclohexane
Axial vs equatorial conformer demo
Methyllithium
Methyl carbanion source
Morpholine
O+N heterocycle; corrosion inhibitor
n-BuLi
Strong base + alkyl carbanion source
NaBH4
Mild hydride reductant
Naphthalene
Bicyclic PAH; mothballs
Neopentane
Highly branched C5; tetrahedrally symmetric
NMP
Battery slurry + Li-ion solvent
Nonane
Mid-distillate hydrocarbon
Norbornane
Bicyclic[2.2.1] scaffold; bridge-bond textbook
o-Cresol
Disinfectant; resin component
o-Xylene
ortho-dimethylbenzene; phthalic acid feedstock
Octane
Gasoline component
Oxalic acid
Dicarboxylic; calcium binder; rhubarb
Oxalyl chloride
Swern oxidation activator + acyl chloride prep
Oxazole
O+N 5-ring; natural product scaffold
Oxetane
Strained 4-ring ether; drug discovery motif
p-Xylene
para-dimethylbenzene; PET feedstock
Pentaerythritol
PETN explosive precursor; resin polyol
Pentane
Low-boiling solvent; foam blowing
Phenanthrene
Angular tricyclic PAH
Phenol
Weakly acidic OH; antiseptic origin; resin monomer
Phenylacetylene
Sonogashira coupling substrate
Phloroglucinol
1,3,5-triol; antispasmodic; explosives
Phthalic acid
Plasticizer feedstock
Phthalic anhydride
Plasticizer + dye precursor
Piperazine
Saturated 1,4-diazine; pharmacophore
Piperidine
Saturated 6-ring; pharmacophore
Propane
LPG fuel; bottled gas
Propene
Polypropylene monomer; Markovnikov demo
Propionaldehyde
C3 aldehyde; plastic precursor
Propionic acid
Preservative; mold inhibitor
Propylene glycol
Food humectant; e-cig vapor base
Propylene oxide
Chiral epoxide; polyether monomer
Propyne
Methylacetylene; terminal alkyne
Pteridine
Folic acid + butterfly pigment core
Purine
Adenine/guanine core
Pyrazine
1,4-diazine; flavor compound (popcorn)
Pyrazole
1,2-diazole; drug scaffold
Pyridazine
1,2-diazine
Pyridine
6-ring aromatic N; weak base; common solvent
Pyridine (basic)
Weakly basic aromatic N; common base solvent
Pyrimidine
1,3-diazine; cytosine/thymine/uracil core
Pyrogallol
1,2,3-trihydroxybenzene; oxygen absorber
Pyrrole
5-ring aromatic NH; porphyrin building block
Quinoline
Fused N-heterocycle; quinine scaffold
Quinoxaline
Anticancer scaffold
Resorcinol
1,3-dihydroxybenzene; sunscreen ingredient
Salicylic acid
Aspirin precursor; acne treatment
sec-Butanol
Secondary alcohol; ketone source
SN2 trigonal bipyramidal transition state
Geometric apex of Walden inversion. 3 H equatorial, Br/I axial along ±z.
Sorbitol
Sugar alcohol; humectant
Squalane
Hydrogenated squalene; cosmetic emollient
Styrene
Polystyrene monomer
Succinic acid
TCA cycle intermediate
Succinic anhydride
Acylation reagent
Sulfuryl chloride
Chlorinating agent
Tartaric acid
Wine acid; Pasteur's chirality discovery
Terephthalic acid
PET polyester monomer
tert-Butanol
Tertiary alcohol; high freezing point
tert-Butyl cation
Stabilized 3° carbocation; SN1/E1 intermediate
tert-Butyl chloride
Tertiary; SN1 textbook substrate
Tetrafluoroethylene
PTFE monomer
Tetrahydrofuran
THF; common Grignard solvent
Tetrakis(triphenylphosphine)palladium(0)
Cross-coupling Pd(0) catalyst
Tetrazole
Bioisostere of carboxylic acid
Thiazole
S+N 5-ring; vitamin B1 core
Thiazoline
Penicillin precursor structural unit
Thionyl chloride
OH→Cl conversion; acyl chloride prep
Thiophene
5-ring aromatic S-heterocycle; conducting polymer backbone
Thymol
Thyme essential oil; antiseptic
trans-2-Butene
trans isomer; more stable than cis
trans-Decalin
Locked diequatorial chair-chair
Triethylamine
Non-nucleophilic base; common in coupling
Trifluoromethane (fluoroform)
Greenhouse gas; refrigerant byproduct
Trimethylamine
Tertiary amine; fish odor
Triphenylmethane
Trityl cation precursor; dye scaffold
Triptycene
D3h rigid 3D scaffold
Valeric acid
Pentanoic acid; valerian root
Vinyl acetate
PVA polymer precursor
Vinyl chloride
PVC monomer; carcinogen
Vinyl fluoride
Fluoropolymer monomer
Wilkinson's catalyst
Homogeneous alkene hydrogenation
Xylitol
Sugar alcohol; sugar-free sweetener