Related topics: molecules

Cutting acrylamide in fried and baked snacks

In 2002, the discovery of acrylamide in certain snacks rattled consumers and the food industry. Acrylamide, a probable human carcinogen, forms by a chemical reaction during baking or frying. Although experts say it's impossible ...

A way to repair tooth enamel

A team of researchers from Zhejiang University and Xiamen University has found a way to repair human tooth enamel. In their paper published in the journal Science Advances, the group describes their process and how well it ...

Analyzing the world's oldest woody plant fossil

Mapping the evolution of life on Earth requires a detailed understanding of the fossil record, and scientists are using synchrotron-based technologies to look back—way, way back—at the cell structure and chemistry of ...

Flame retardants—from plants

Flame retardants are present in thousands of everyday items, from clothing to furniture to electronics. Although these substances can help prevent fire-related injuries and deaths, they could have harmful effects on human ...

Scientists find longevity biomarkers

An international group of scientists studied the effects of 17 lifespan-extending interventions on gene activity in mice and discovered genetic biomarkers of longevity. The results of their study were published in the journal ...

Graphene nanoflakes: A new tool for precision medicine

Chemists funded by the SNSF have created a new compound for flexible drug delivery that specifically targets prostate cancer cells. Incorporating four different molecules, the compound prevents tumor cells from multiplying, ...

Catalytic transformation of ethylene

National University of Singapore chemists have developed a catalytic method using visible light for the difunctionalization of ethylene for potential use in the production of fine chemicals.

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Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions and that have a unique and defined chemical structure. Chemical compounds consist of a fixed ratio of atoms that are held together in a defined spatial arrangement by chemical bonds. Chemical compounds can be compound molecules held together by covalent bonds, salts held together by ionic bonds, metallic compounds held together by metallic bonds, or complexes held together by coordinate covalent bonds. Substances such as pure chemical elements and elemental molecules consisting of multiple atoms of a single element (such as H2, S8, etc.) are not considered chemical compounds.

Elements form compounds to become more stable. They become stable when they have the maximum number of possible electrons in their outermost energy level, which is normally two or eight valence electrons. This is the reason that noble gases do not frequently react: they already possess eight valence electrons (the exception being helium, which requires only two valence electrons to achieve stability).

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