The memory metal, nitinol, is an alloy of nickel and titanium. It is called a memory metal because after being deformed, a piece of nitinol wire will return to its original shape. The structure of nitinol consists of a simple cubic array of Ni atoms and an inner penetrating simple cubic array of Ti atoms. In the extended lattice, a Ti atom is found at the center of a cube of Ni atoms; the reverse is also true. a. Describe the unit cell for nitinol. b. What is the empirical formula of nitinol? c. What are the coordination numbers (number of nearest neighbors) of Ni and Ti in nitinol?

Interpretation:

The unit cell of Nitinol – An alloy of Nickel and Titanium has to be described.

Concept introduction:

The simplest and basic unit of a crystalline solid is known as unit cell.  It is cubic in shape. It is the building block of crystalline solids. The unit cells repeat themselves to build a lattice. Crystalline solids consist of many of such lattices. There are three types of unit cell – simple cubic unit cell, body – centered cubic unit cell and face – centered cubic unit cell.

A simple cubic unit cell is the simplest form of a cubic unit cell. A cube has eight vertices, twelve edges and six faces. Similarly a cubic unit cell has eight vertices, twelve edges and six faces. If in a cubic unit cell, the components occupy only the eight vertices, then the unit cell is known as simple cubic unit cell.

In a body – centered cubic cell is another type of unit cell in which atoms are arranged in all the eight vertices of the unit cell with one atom per vertex. Further one atom occupies the center of the cube.

In a face – centered cubic cell the atoms are arranged in all the eight vertices of the unit cell with one atom per vertex. Further all the six faces of a cubic unit cell are occupied with one atom per face.

Co ordination number of any atom in close packing of solids is known as the number of adjacent atoms it is surrounded by.

Unit cell of Nitinol

Understand the arrangement of Nickel and Titanium atoms in Nitinol.

A simple cubic array of Nickel atoms is penetrated inwards by simple cubic array of Titanium atoms. At the center of a cube of Nickel atoms a Titanium atom is occupied...

Interpretation:

The empirical formula of Nitinol has to be deduced.

Concept introduction:

The simplest and basic unit of a crystalline solid is known as unit cell.  It is cubic in shape. It is the building block of crystalline solids. The unit cells repeat themselves to build a lattice. Crystalline solids consist of many of such lattices. There are three types of unit cell – simple cubic unit cell, body – centered cubic unit cell and face – centered cubic unit cell.

A simple cubic unit cell is the simplest form of a cubic unit cell. A cube has eight vertices, twelve edges and six faces. Similarly a cubic unit cell has eight vertices, twelve edges and six faces. If in a cubic unit cell, the components occupy only the eight vertices, then the unit cell is known as simple cubic unit cell.

In a body – centered cubic cell is another type of unit cell in which atoms are arranged in all the eight vertices of the unit cell with one atom per vertex. Further one atom occupies the center of the cube.

In a face – centered cubic cell the atoms are arranged in all the eight vertices of the unit cell with one atom per vertex. Further all the six faces of a cubic unit cell are occupied with one atom per face.

Co ordination number of any atom in close packing of solids is known as the number of adjacent atoms it is surrounded by.

Interpretation:

The co ordination numbers of Nickel and Titanium has to be found.

Concept introduction:

The simplest and basic unit of a crystalline solid is known as unit cell.  It is cubic in shape. It is the building block of crystalline solids. The unit cells repeat themselves to build a lattice. Crystalline solids consist of many of such lattices. There are three types of unit cell – simple cubic unit cell, body – centered cubic unit cell and face – centered cubic unit cell.

A simple cubic unit cell is the simplest form of a cubic unit cell. A cube has eight vertices, twelve edges and six faces. Similarly a cubic unit cell has eight vertices, twelve edges and six faces. If in a cubic unit cell, the components occupy only the eight vertices, then the unit cell is known as simple cubic unit cell.

In a body – centered cubic cell is another type of unit cell in which atoms are arranged in all the eight vertices of the unit cell with one atom per vertex. Further one atom occupies the center of the cube.

In a face – centered cubic cell the atoms are arranged in all the eight vertices of the unit cell with one atom per vertex. Further all the six faces of a cubic unit cell are occupied with one atom per face.

Co ordination number of any atom in close packing of solids is known as the number of adjacent atoms it is surrounded by.