The high-yield syntheses of 6-X-B10H13 [X = Cl (88%), Br (96%), I (84%)] resulted from the cage-opening reactions of the (NH4+)(2)B10H102- salt with ionic-liquid-based superacidic hydrogen halides, while both the previously unknown 6-F-B10H13 (77%) derivative and 6-0-B10H13 (90%) were synthesized in high yields via the reactions of (NH4+)(2)B10H102- with triflic acid in the presence of 1-fluoropentane and dichloromethane, respectively. Structural characterizations of 1-4 confirm the predicted structures and indicate strong halogen back-bonding interactions with the 136 boron. The reaction of 6-Br-B10H13 with Bu3SnH produced the parent B10H14 in 70% yield, and thus, this reaction, in conjunction with the haloacid-induced closo-B10H102- cage-opening reactions, has the potential to provide an alternative to the traditional diborane pyrolysis route to decaborane.