Organic vs Inorganic
In chemistry, organic compounds are those built around carbon — almost always containing carbon-hydrogen bonds. Inorganic compounds are everything else: salts, metals, minerals, and most simple compounds without carbon-hydrogen bonds. The word "organic" also has a separate everyday meaning in food and farming, which doesn't match the chemistry definition.
Last reviewed on 2026-04-27.
Quick Comparison
| Aspect | Organic | Inorganic |
|---|---|---|
| Chemistry definition | Contains C–H bonds (carbon-based) | Does not contain C–H bonds (or is otherwise non-carbon-based) |
| Examples | Methane, sugars, proteins, plastics, alcohols, fuels | Water, salt, sand, metals, most acids and bases |
| Sources | Living things, oil, synthesis from other organic compounds | Minerals, geological processes, pure elements |
| Behaviour | Often flammable, lower melting points, complex structures | Often non-flammable, higher melting points, simpler structures |
| Edge cases | CO2, carbonates — usually classified inorganic despite carbon | Same — definitions have historical exceptions |
| Food labelling | Often refers to farming methods (no synthetic pesticides, etc.) | Not typically used in food labelling |
Key Differences
1. The chemistry definition
In chemistry, an organic compound is one that contains a carbon-hydrogen bond. The category covers an enormous space: methane, ethanol, benzene, glucose, proteins, plastics, oils, every fuel from petrol to natural gas.
Inorganic compounds are the rest — water, salt, sand, metals, simple acids and bases, minerals. There's no single defining structural feature; the category is essentially "not organic."
2. Why carbon is special
Carbon forms four covalent bonds and can connect to itself in long chains, branches, and rings. That capacity for variety is why over 99% of known compounds are organic — there's simply more variation possible with carbon than without.
Other elements form fewer or simpler bonds with themselves, leading to a much smaller catalogue of stable structures.
3. Sources
Organic compounds are produced by living things, by petroleum and natural gas reserves (which are themselves derived from ancient organisms), and by chemical synthesis from other organic starting materials.
Inorganic compounds come from minerals, geological processes, and pure elemental sources. Salt from seawater, iron from ore, silicon from sand — all inorganic.
4. Common properties
Organic compounds tend to be flammable (they contain carbon and hydrogen, which combine readily with oxygen in fire), have lower melting and boiling points, and form complex three-dimensional structures.
Inorganic compounds tend to be less flammable (often not flammable at all), have higher melting points, and form simpler crystalline structures.
5. Edge cases
Carbon dioxide (CO2) contains carbon but no C–H bonds and is conventionally classified as inorganic. Same for carbonates (calcium carbonate, sodium bicarbonate) and carbides.
These exceptions exist because the definition is partly historical: "organic" originally meant "derived from living things" before the discovery that organic chemistry can be done synthetically. The C–H rule is the modern shorthand but isn't airtight.
6. The food meaning
In food and agriculture, "organic" means the food was produced under specific certified standards: no synthetic pesticides, no synthetic fertilisers, no GMOs, certain animal welfare standards, etc. Specific rules vary by country (USDA in the U.S., Soil Association and EU rules in Europe).
This is unrelated to the chemistry definition. All food is chemically organic in the carbon-based sense, regardless of how it's farmed.
When to Choose Each
Choose Organic if:
- Discussing chemistry of biological molecules, fuels, plastics, pharmaceuticals.
- Almost every reaction in living organisms involves organic compounds.
- Petrochemistry, polymer science, biochemistry.
Choose Inorganic if:
- Discussing salts, minerals, metals, and most reactions in geology and metallurgy.
- Industrial processes involving acids, bases, ceramics.
- Most of what's in the periodic table's elemental and salt-based chemistry.
Worked example
In a chemistry lab, a student dissolves table salt (sodium chloride, an inorganic compound) in water (also inorganic) and adds glucose (an organic compound). All three are dissolved, mixing two inorganics with one organic. In a different setting, a customer at a market buys "organic apples" — meaning produced under certified organic farming methods. Chemically, those apples and any other apples have the same carbon-based makeup; the label refers to the farming, not the chemistry.
Common Mistakes
- "Organic means natural, inorganic means synthetic." Both natural and synthetic organic compounds exist (oil is organic and natural; plastics are organic and synthetic). Both natural and synthetic inorganic compounds exist similarly.
- "Organic food contains organic chemistry." All food does. The food meaning is about farming, not molecules.
- "All carbon-containing compounds are organic." Carbon dioxide, carbonates, and a few others are conventionally inorganic.
- "Inorganic means lifeless or unimportant." Water, oxygen, and many minerals are inorganic and absolutely essential to life.