Library of Congress call numbers group books by topic. There is no single call number range that covers all materials pertaining to Islam, but the following is a sample of call numbers you might find useful.
BP 1 - 253 Islam
BP 1 - 68 General
BP 100 - 134 Koran
BP 160 - 165 General works on Islam
BP 174 - 190 The Practice of Islam
BP 191 - 253 Branches, sects. etc.
DS 41 - 392 - Islamic countries of Asia
DS 43 - 346 - Islamic countries of North Africa