What Are Inorganic Substances?

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Most inorganic compounds do not contain carbon; however, in those inorganic substances that do contain carbon, carbon-hydrogen bonds are absent. Organic compounds always contain carbon and almost all have carbon-hydrogen bonds, according to About.com

Organic compounds are associated with living material. In addition to straight chain hydrocarbons, organic chemicals include fats, sugars nucleic acids, enzymes, proteins and other molecules the organism uses for food.

Salts are examples of inorganic compounds. Sodium chloride, which is common table salt, forms cubic crystals. It is an ionic compound that is highly soluble in water, dissociating to form sodium ions and chlorine ions. Some salts are clear or white, while others, such as copper sulfate, are highly colored.

Rocks and minerals are other types of inorganic compounds. While some sedimentary rocks contain organic compounds, heat burns the carbon from most igneous and metamorphic rocks to form carbon dioxide, leaving only the minerals behind.

Coal, made of organic material from wood, pollen and cell walls, is a maceral. However, as the earth applies pressure to coal for an extended period, the maceral loses all other elements except for carbon and forms graphite. While organic in origin, graphite and the harder form of carbon, diamonds, are minerals. Once they lose the other elements, they become inorganic.