7. give the miller indices for a crystal face that is parallel to the a and b axes of a crystal and intersects the c axis at a length of negative one.

The Miller Indices of the crystal are: [0, 0, - 1]

Solution:

As per the question:

For a plane parallel to a and b axes and intersect c axis at - 1, the intercepts made on the axes are respectively:

Intercept on a-axis =

Intercept on b-axis =

Intercept on c-axis = - 1

Now,

Weiss parameters are

Now,

The Miller indices are given as the reciprocal of Weiss parameter as:

a = = 0

b = = 0

c = - 1

Thus

The Miller Indices are: [0, 0, - 1]

an angle + its complement = 90 degrees