Ionization of polar liquids and glasses often yields metastable electron centers known as 'weakly bound' (wb) electrons that absorb to the red of the ground state of the solvated/trapped electron. In this Letter, we address the structure of the wb electron in low-temperature ice-I-h theoretically. The comparison with the observed properties suggests that this species is an s-like electron filling a water vacancy. (C) 2007 Published by Elsevier B.V.