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Similarly, yellow arsenic is a molecular solid composed of As 4 units. [37] Some forms of sulfur and selenium are composed of S 8 (or Se 8) units and are molecular solids at ambient conditions, but converted into covalent allotropes having atomic chains extending throughout the crystal. [38] [39]
Solid: A solid holds a definite shape and volume without the need of a container. The particles are held very close to each other. Amorphous solid: A solid in which there is no far-range order of the positions of the atoms. Crystalline solid: A solid in which atoms, molecules, or ions are packed in regular order.
A solid with extensive hydrogen bonding will be considered a molecular solid, yet strong hydrogen bonds can have a significant degree of covalent character. As noted above, covalent and ionic bonds form a continuum between shared and transferred electrons; covalent and weak bonds form a continuum between shared and unshared electrons.
In a solid, constituent particles (ions, atoms, or molecules) are closely packed together. The forces between particles are so strong that the particles cannot move freely but can only vibrate. As a result, a solid has a stable, definite shape, and a definite volume. Solids can only change their shape by an outside force, as when broken or cut.
Some chemical substances can be combined or converted into new substances by means of chemical reactions. Chemicals that do not possess this ability are said to be inert . Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a single oxygen atom (i.e. H 2 O).
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound.
Solid-phase electrical conductivity: Variable, [6] depending on the nature of the bonding: network solids in which all electrons are used for sigma bonds (e.g. diamond, quartz) are poor conductors, as there are no delocalized electrons. However, network solids with delocalized pi bonds (e.g. graphite) or dopants can exhibit metal-like conductivity.
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. [1] [2] Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. [3]