Body-Centered Cubic Crystals
The body-centered cubic (BCC) lattice is one of the simplest cubic crystal systems, adopted by many metals. Explore it in this live AIMS simulation.
The body-centered cubic lattice (BCC) is a cubic crystal system with an atom at each corner of the cube and one at its center. Many metals — such as iron, chromium, tungsten, and the alkali metals — adopt this arrangement. Explore the BCC structure in the live AIMS model below.
How the Atoms Are Arranged
In a body-centered cubic crystal, atoms sit at the eight corners of a cube with a single atom at its very center. Each atom has eight nearest neighbors — a coordination number of 8 — and the atoms fill about 68% of space. That is slightly less dense than the close-packed FCC and HCP structures, and BCC has no truly close-packed planes. This difference helps explain why many BCC metals, such as iron, chromium, and tungsten, tend to be strong and hard, and why some of them turn brittle at low temperatures.
Simulated with the Embedded-Atom Method
Metallic bonding cannot be captured by simple pairwise springs, because the strength of the bond between two atoms depends on how many other atoms surround them. This simulation therefore uses embedded-atom method (EAM) force fields, in which each atom's energy includes a term for embedding it in the local electron density contributed by its neighbors. EAM potentials reproduce the elastic and structural properties of real metals far more faithfully than pair potentials, which is what makes a realistic molecular dynamics simulation of BCC metals possible here.
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