Hello there, 

I have never used R so I am not sure if it is helpful, but please see the attached file (page 2) and also video link.

Best wishes

https://www.youtube.com/watch?v=60A3YxU2hCw

Cho (2016) – https://doi.org/10.1177/1094428116656239 – argues that the term “Cronbach’s alpha” should be avoided. Call it tau-equivalent reliability (rho T) instead! However, don't report rho T, if the factor loadings differ between the items, which is often the case. In these cases, use congeneric reliability (rho C) instead. Finally, don't use rho T or rho C as "cutoff" values. They might help you to make a decision, but they should not make the decision for you! See for example Guide & Ketokivi (2015): https://doi.org/10.1016/S0272-6963(15)00056-X