Is it permissible to miss congregational prayers due to studying, and should one pray alone at school or delay the prayer until returning home?

Congregational prayer is obligatory, but most of those who deem it obligatory do not stipulate that it must be performed in the mosque. Thus, it can be performed with colleagues or at home. If that is not possible, or if there is a considerable harm in attending it at the mosque, there is no sin in leaving it, for the religion is easy. The Lawgiver has permitted leaving the congregation for an excuse. If it is possible to go out without harm, then pray in the mosque; otherwise, there is no sin in staying behind.