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Negative indices

To index this plane it is useful to use a different corner of the unit cell as the point of reference.

Go along the positive *x* and *z* axes to find those intercepts.

Then go backwards along the negative *y*-axis, to get a negative
intercept.

Instead of using a minus sign, we use an 'overbar' to denote a negative index. This gives a Miller Index of:

(112)

This reads as "one, bar one, two".