Can not.Chemistry is one of those things that just cannot be planned for when casting a film....
At present, if you draw a company pension you cannot go back to work for that company.
The workload in Bradford is so great that it cannot take on any new clients at present.
Usage
Both the one-word form cannot and the two-word form can not are acceptable, but cannot is more common (in the Oxford English Corpus, three times as common). The two-word form is better only in a construction in which not is part of a set phrase, such as ‘not only ... but (also)’: Paul can not only sing well, he also paints brilliantly.