Question

Calculate the dhkl of tetragonal using the concepts of

reciprocal lattic​

Answer 1

Explanation:

case of P. Grima Gallardo's answer the hk0 and 00l are NO lattice planes but describe reciprocal lattice vectors (Laue indices). In his sentence it should be written: "...using the (hk0) or (001)-planes...", i.e. then no 00l. Also a (220) does not exists but only a (110). You can try to find lattice points describing a plane (220). For an I-lattice there is no lattice plane. For an F-lattice points exist for a (220) but by definition Miller indices are given by numbers which have to be prime to each other.

Igor description is also OK but the distance dhkl does not define always the interplanar distance but the length of the reciprocal lattice vector hkl. He can really use any combination of h,k and l. However, if he wants describe the distance of lattice planes he needs to write d(hkl) and then again h,k and l have to be prime to each other. (hkl) define Miller indices, hkl are Laue indices.

This also has some effects on Bragg's equation, i.e., how it is written:

n λ =2 d(hkl) sin θhkl=2 d(hkl) sin θn(hkl)

i.e. θ is always related to the hkl and not to (hkl).

Or one simply writes:

λ = 2 dhkl sin θhkl

so that follows: d(hkl)/n = dhkl