We established that the transformation from Si-5(2-) to Al5H52- could be possible by the successive isoelectronic substitution of silicon atoms by Al-H units. The potential energy surfaces for the series Si5-n(AlH)(n)(2-) (n = 0-5) systems were explored in detail, and the global minima maintained the same overall deltahedral structure as the one of the Si-5(2-) cluster. The conservation of the overall structure upon isoelectronic substitution was proven to happen due to the preservation of the chemical bonding pattern. Theoretical VDEs were calculated for the series LiSi5-n(AlH)(n)- (n = 1-4) systems to facilitate their experimental detection. (C) 2016 Elsevier B.V. All rights reserved.