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Wavy single bonds represent unknown or unspecified stereochemistry or a mixture of isomers. For example, the adjacent diagram shows the fructose molecule with a wavy bond to the HOCH 2 - group at the left. In this case the two possible ring structures are in chemical equilibrium with each other and also with the open-chain structure.
[16] [17] [18] A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with two atoms in the oxygen molecule (O 2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (two hydrogen atoms and one oxygen atom; H 2 O). A molecule is the smallest unit of a substance that ...
Two or more elements combined into one substance through a chemical reaction form a chemical compound. All compounds are substances, but not all substances are compounds. A chemical compound can be either atoms bonded together in molecules or crystals in which atoms, molecules or ions form a crystalline lattice.
The IUPAC definition of a solid solution is a "solid in which components are compatible and form a unique phase". [3]The definition "crystal containing a second constituent which fits into and is distributed in the lattice of the host crystal" given in refs., [4] [5] is not general and, thus, is not recommended.
A diagram representing at the microscopic level the differences between homogeneous mixtures, heterogeneous mixtures, compounds, and elements. Mixtures can be either homogeneous or heterogeneous: a mixture of uniform composition and in which all components are in the same phase, such as salt in water, is called homogeneous, whereas a mixture of ...
Chemical structures are presented to help readers understand the nature of the titled material. One can subdivide chemical compounds into two main groups: molecules, which includes most organic, polyatomic gases, and organometallic compounds, and nonmolecular species, which includes most purely inorganic compounds.
For example, N 2-emission bands (a.k.a. Vegard-Kaplan bands) are present in the spectral range from 0.14 to 1.45 μm (micrometres). [9] A given band can be spread out over several nanometers in electromagnetic wavelength space, owing to the various transitions that occur in the molecule's rotational quantum number, J {\displaystyle J} .
A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus.