What is a tetrahedral site in a closest-packed lattice formed by?

Verified step by step guidance

Understand that a closest-packed lattice refers to the arrangement of atoms in a crystal structure where they are packed as closely as possible.

Recognize that in a closest-packed structure, there are two main types of interstitial sites: tetrahedral and octahedral.

A tetrahedral site is formed when four atoms are arranged in a tetrahedron, creating a small space or void in the center.

Visualize that in a face-centered cubic (FCC) or hexagonal close-packed (HCP) lattice, the tetrahedral sites are located between the layers of atoms.

Remember that these sites are important because they can be occupied by smaller atoms or ions, influencing the properties of the material.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Closest-Packed Lattice

A closest-packed lattice is a type of crystal structure where atoms are packed together as closely as possible, maximizing density. The two most common arrangements are face-centered cubic (FCC) and hexagonal close-packed (HCP). In these structures, atoms occupy specific positions that minimize empty space, leading to efficient packing and stability.

Tetrahedral Coordination

Tetrahedral coordination refers to a geometric arrangement where a central atom is surrounded by four other atoms at the corners of a tetrahedron. In a closest-packed lattice, tetrahedral sites are formed when four atoms from the lattice surround a central atom, allowing for specific bonding and spatial arrangements that influence the properties of the material.

Interstices in Crystal Structures

Interstices are the small spaces or voids between atoms in a crystal lattice. In closest-packed structures, there are two main types of interstitial sites: octahedral and tetrahedral. Tetrahedral sites specifically accommodate smaller atoms or ions, which can fit into these voids without disrupting the overall lattice structure, playing a crucial role in the properties of alloys and compounds.

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Textbook Question

An unknown metal is found to have a density of 7.8748 g/cm³ and to crystallize in a body-centered cubic lattice. The edge of the unit cell is 0.28664 nm. Calculate the atomic mass of the metal.

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Textbook Question

Calculate the fraction of empty space in cubic closest packing to five significant figures.

Textbook Question

X-ray diffractometers often use metals that have had their core electrons excited as a source of X-rays. Consider the 2p → 1s transition for copper, which is called the K⍺ transition. Calculate the wavelength of X-rays (in Å) given off by the K⍺ transition if the energy given off by a mole of copper atoms is 7.77⨉10⁵ kJ.(1Å = 10^-10 m)

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