Correct use of "consist"

Which one of the following two sentences is correct?

1. We are only concerned with crystal systems which consist of an inversion center.
2. We are only concerned with crystal systems which consist an inversion center.

I really can't tell the difference. If they are both grammatically correct, which usage is more formal? (I hope I am not being too vague).

Solution 1:

The verb consist is never used without a preposition and it usually takes either of or in. In your example, it should be consist of. Thus, the first sentence is correct while the second is wrong. From the Oxford Dictionaries:

1 (consist of) be composed or made up of

• (consist in) have as an essential feature

2 (consist with) archaic be consistent with

I should also add that it is probably not uncommon for some speakers to drop the of in conversation, but this should by all means be avoided in written contexts.

Solution 2:

Consist of means "be composed or made up of". The NOAD reports three different meanings of consist, but the verb is always used with a preposition: consist of, consist in, consist with.

The exhibition consists of 180 drawings.
His duties consist in taking the condition of the barometer.
The information perfectly consists with our friend's account.

If I understood what you mean, I would write the sentence as:

We are only concerned with crystal systems consisting of an inversion center.