Vibrational modes in BiOCl

[![enter image description here](https://i.stack.imgur.com/xIa69.png)](https://i.stack.imgur.com/xIa69.png)


These are the vibrational modes in BiOCl. I'm trying to account for the each mode, and where in the spectrum you would find such mode. And I found out that at 1400 cm-1 you have asymmetric stretch of bi-cl (Eu), at 1040 cm-1 there is symmetric stretch of bi-cl (A2u), and at 528 there is a symmetric stretching mode (A2u). Which leaves an Eu mode. 
I've looked through many research papers, and they all seem to use microspheres of biocl, and there's often OH bands due to water vapour, but none have modes. What can be a reason for this? and what should the 4th mode be?
This is an example of FTIR spectrum I've seen:
[![enter image description here](https://i.stack.imgur.com/F9IsD.png)](https://i.stack.imgur.com/F9IsD.png)


