Chemical state

The chemical state of a chemical element is its electronic, chemical and physical nature as it exists in combination with a group of one or more other elements or in its natural "elemental state". Material scientists, solid state physicists, analytical chemists, surface scientists and spectroscopists describe or characterize the chemical, physical and/or electronic nature of the surface or the bulk regions of a material as having or existing as one or more chemical states.

The chemical state set comprises and encompasses these subordinate groups and entities: chemical species, functional group, anion, cation, oxidation state, chemical compound and elemental forms of an element.

This term or phrase is commonly used when interpreting data from analytical techniques such as:

The chemical state of a group of elements, can be similar to, but not identical to, the chemical state of another similar group of elements because the two groups have different ratios of the same elements and exhibit different chemical, electronic, and physical properties that can be detected by various spectroscopic techniques.

A chemical state can exist on or inside the surface of a solid state material and can often, but not always, be isolated or separated from the other chemical species found on the surface of that material. Surface scientists, spectroscopists, chemical analysts, and material scientists frequently describe the chemical nature of the chemical species, functional group, anion, or cation detected on the surface and near the surface of a solid state material as its chemical state.

To understand how a chemical state differs from an oxidation state, anion, or cation, compare sodium fluoride (NaF) to poly-tetrafluoro-ethylene (PTFE, Teflon TM). Both contain fluorine, the most electronegative element, but only NaF dissolves in water to form separate ions, Na+ and F-. The electronegativity of the fluorine strongly polarizes the electron density that exists between the carbon and the fluorine, but not enough to produce ions which would allow it to dissolve in the water. The carbon and fluorine in Teflon (PTFE) both have a zero (0) electronic charge since they form a covalent bond, but few scientists describe those elements as having a zero oxidation state. On the other hand, many elements, in their pure form, are often described as existing with a zero oxidation state. This is one of the attributes of nomenclature that has been upheld over the years.

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