In the procedure to determine Miller indices from intercepts, what is the third step?

• A. Find point plane intercepts axis
• B. Take reciprocal
• C. Multiply across by LCM
• D. Encase in parentheses

Answer: (B)

Converting intercepts to Miller indices relies on turning those intercept values into integers by using reciprocals and then clearing fractions. After you locate where the plane meets the three axes in units of the lattice constants, you take reciprocals of those intercepts to get numbers proportional to h, k, and l. Those reciprocals can be fractions, so the next move is to multiply all three by the least common multiple of the denominators to obtain the smallest whole-number set. Only after you have integers do you enclose them in parentheses to denote the Miller indices. So the third step is multiplying by the LCM to clear fractions, not taking the reciprocal again.