Chemical Structure of Potassium Chloride

Updated April 17, 2017

Potassium chloride is a chemical made up of one potassium atom and one chloride atom. It has a molecular weight of 74.55. Potassium makes up 52.4 per cent of the compound while chloride makes up 47.6 per cent of the molecule. It's molecular structure is a face-centred cubic lattice.

Physical Properties

Potassium chloride is a metal halide salt. At room temperature it exists as white crystals or a crystalline powder. It can also exist as white granular powder or colourless, odourless crystals. It has a saline taste.

Chemical Structure

At the molecular level potassium chloride exists as a crystalline structure, like many other halide salts. It appears as a face-centred cube. The cube has repeating units that extend in all directions. The arrangement of the K and Cl ions in the cube forms what is called a lattice. In halide salts, such as NaCl and KCl, the crystal lattice formation is highly ordered, having regular, repeating patterns of ions.

Comparison to Other Halide Structures

All halide salts and in fact all ionic solid cubes are similar in structure. However, they are not completely identical. Factors that affect the size and shape of their structure include the degree of packing between the ions and the relative size of the ions themselves.

Specific Structure of the Potassium Chloride Crystal Lattice

The overall characteristics of the crystal lattice structure in potassium chloride are characterised by the lattice constant. The lattice constant is the constant distance between the individual potassium or chloride atoms in the crystal lattice. For potasisum chloride the lattice constant is 6.29 angstroms.

Further Information about Potassium Chloride Structures

The crystal lattice structure of potassium chloride is soluble in water. It has a density of 1.98 g/cm3 at 20 degrees Celsius and a melting temperature of 1050 Kelvin, which is equal to 1,430.33 degrees Fahrenheit or 766.66 degrees Celsius.

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About the Author

Robin Wasserman has been writing and prosecuting biochemical patents since 1998. She has served as a biochemical patent agent and a research scientist for a gene-therapy company. Wasserman earned her Doctor of Philosophy in biochemistry and molecular biology, graduating from Harvard University in 1995.