Body-Centered Cubic bcc and Simple Hexagonal Structures

Two other crystaUine structures which are not close-packed must be mentioned here the body-centered cubic bcc) and the simple hexagonal ijtex). The bcc structure is a common structure of early transition metals and is shown in Fig. 3.12. Each atom has only eight equidistant nearest neighbors instead of twelve for close-packed systems (coordination number = 8), and the structure has a lower density with a volume per atom 

The simple hexagonal (hex) unit cell is shown in Fig. 3.13 typically represented by the WC structure (see Sec. 5.0). 

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