Related topics: molecules

Building better gas-phase biosensors for fight against diseases

Scientists from the Tokyo Medical and Dental University (TMDU) introduce an easy method for manufacturing biosensors made from electrospun polymers. By embedding enzymes inside the polymer string, the enzymes were operational ...

Researchers find key to solving serious wine grape issue

Grapevine Trunk Diseases, or GTDs, are the bane of vineyard owners worldwide, and as of 2012, were responsible for more than $1.5 billion in annual economic damages. While researchers have long known that a host of pathogenic ...

Webb reveals cosmic cliffs, glittering landscape of star birth

This landscape of "mountains" and "valleys" speckled with glittering stars is actually the edge of a nearby, young, star-forming region called NGC 3324 in the Carina Nebula. Captured in infrared light by NASA's new James ...

Prospecting for interstellar oil

We have developed a new method to look for carbon compounds in space, akin to prospecting for oil on Earth. Our method is published in Monthly Notices of the Royal Astronomical Society.

Hunting down toxic substances in sludge

Analytical chemists Gabriela Castro Varela and Alexandros Asimakopoulos are hunting for toxic and unregulated chemical substances in the sewage sludge that is a by-product from the water treatment plants of Trondheim municipality.

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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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