Dear Brother/Sister, while reading some fatawa online, I came across Dr Zakir Naik's statement below:
There are five types of divorce in Islam – The first type is by unilateral… by unilateral agreement, between the husband and wife – Both may say… ‘Okay, we are not compatible… let us part’.
Can you explain this type of divorce. In this case, does the husband need to say the proper wordings or only the statement mentioned above? Thank you.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger. 

The saying of the husband to his wife, “We are not compatible… let us part,” etc., is not an explicit wording of divorce. The explicit wording of divorce is that which includes the word divorce and what is conjugated of it other than the present tense or the imperative mood, as stated by the jurists (scholars of Fiqh).

Some scholars of Fiqh are of the view that the word separation (or parting) is an explicit word of divorce; Ibn Qudaamah said, “This requires that explicit words of divorce are three: Talaaq (divorce), Firaaq (separation), and Tasreeh (releasing someone or letting someone free), and the different forms derived from them. This is the view of Ash-Shaafi’i. However, Abu ‘Abdullah ibn Haamid is of the view that the explicit word of divorce is only the word divorce and what is conjugated of it, but not other wordings. This is also the view of Abu Haneefah and Maalik...”

In any case, this does not include what is mentioned in the question because it is used in the imperative mood (…let us…) and not in the past tense; so this wording does not make divorce effective.

Allah knows best.