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Unable to install to my new Sony xperia XA
Does your phone has enough free internal storage?
are you installing the app from the playstore?
Hi @Vian_jarvi, welcome to our community!
I'm sorry to hear about the troubles with installing the Facebook application. 
As mentioned by @uliwooly, make sure there is enough free space on the internal storage so the app can be installed. You can see how much free space there is on the internal storage if you go to Settings > Storage > Internal storage.
Are you downloading the Facebook app from the Google Play store? Can you install other applications in your phone from the Google Play store?
When you try and install the application, do you receive any error message along the way?
I'd recommend that you clear data for the Google Play store application, this will not delete any apps, it will only reset the data and cache for the Google Play store app. To do that go into Settings > Apps > Google Play store > Storage > Clear data.
Let me know how it goes! 
If you can install other applications without any trouble, it sounds like its related to just the Facebook applications.
I will not be able to provide any support for a thirdparty application so I'd recommended getting in contact with the Facebook support.
You can reach them by emailing android-support@fb.com or through their homepage www.facebook.com/help.
Let us know how it goes!
It should, keep in mind that Sony has nothing to do with the app, it's up to facebook devs to address any issues.
Settings > apps > playstore > storage > clear data > restart the phone > check again.