First, this seems to be Miller indexing. They are defined as h,k l which are relatively prime to each other. (440) does not exist but (110) and also (622) is nonsense but is correctly indexed by (311).

Second, what you are talking about? Do you see the lattice planes? Can you post an image?

Only in case you are talking about XRD: close to the 321 of the cubic In2O3 the 110 of the rhombohedral In2O3 exist. Can this be your solution, i.e. you also have a mixture of both modifications? 110 is practically the second strongest peak of this modification.

It would be nice - in case you are talking about XRD - if you would post a diffraction pattern.

First, thank you for your answer.

I used JCPDS Card No. 06-0416 In order to determine h,k l.

Why (440) does not exist although this peak indexed in JCPDS Card No. 06-0416.

I want to explain why the (321) appeared in the films dposited at 0.25 M ( I mean high concentration) and the other peaks reduced Knowing that thses peaks were dominant in the films deposited at Low concentrations.

Again, this is not (440) but 440. A lattice plane indexed as (440) does not exist. It is the 4th order interference of lattice plane (110) which is indexed after Laue indexing as 440.

If you look in your diffraction pattern you already see that this peak does not belong to this phase. It is much too narrow!

You are doing spin coating. On what?How big is the width and the step size you were using?

I am quite sure that this is another phase and has nothing to do with a 321 reflection.

First, thank you.

now I understand you ( 440 It is the 4th order interference of lattice plane (110) which is indexed after Laue indexing as 440)

. Films preparation

The prepared solutions were deposited using spin coater where the spinning speed was set at 4000 rpm for 30 s in order to get well coated films. The samples were then undergoing the drying process at 250 °C for 10 min in oven to dry the films and evaporate the organic solvents. After the deposition of sixth layer the samples were annealed in air at 500 °C for 2 h to get crystalline films.

. Measurement conditions

Minimum step size Omega:0.001

Difractometer system = XPERT-PRO

Ratio K-Alpha2/K-Alpha1,0.500

Generator voltage, 40

----- The crystalline form exist in two phases, the cubic In2O3 (bixbyite type) and rhombohedral In2O3 (corundum type). . The rhombohedral phase is produced at high temperatures and pressures or when using non-equilibrium growth methods.

you said that the narrow peak represents another phase. like what ? please, Can you suggest this phase?

Thank you.