NOVELTY - Hydridable alloy comprising metal complex (I), is claimed.    USE - (I) is useful in negative electrode of an alkaline accumulator of the nickel metal hydride type (claimed), where the accumulators are a prismatic format (planar electrodes) or a cylindrical format (spiral or concentric electrodes). The alkaline accumulator is useful in source of energy for an electric vehicle or a portable appliance.    ADVANTAGE - (I) provides active material of the negative electrode having both high intial mass capacity and good lifetime during cycling    DETAILED DESCRIPTION - Hydridable alloy comprising metal complex of formula (R1-x-yMgxMyNis-aB2a), where: at least 5 vol.% of which consists of a stack of sequences with a pattern of the A2B14 type and n patterns of calcium copper (CaCu5) type randomly distributed along one direction, n is an integer comprised of 1-10 and representing the number of patterns of the CaCu5 type per pattern of the A2B14 type; A is one or more elements forming stable hydrides under normal conditions of temperature and of pressure, for e.g. rare earths; and B1 is one or more elements, for which the hydrides are unstable under the same conditions, e.g. nickel, is claimed.    R = group of rare earths and/or yttrium;    M = Zr and/or Ti;    B2 = Mn, Al, Co and/or Fe;    x = 0.1-0.4;    y = 0-0.1;    s = 3-4.5; and    a = 0-1.    INDEPENDENT CLAIMS are included for:    (1) a method for making (I) comprising: (a) mixing magnesium-nickel (Mg2Ni) with a compound comprising (i) nickel, (ii) one or several elements comprising rare earths and yttrium, with optionally titanium and/or zirconium and (iii) optionally an element comprising manganese, aluminum, cobalt and/or iron, (b) milling the mixture, and (c) sintering the mixture by compressing the mixture and applying current through the mixture;    (2) a negative electrode of an alkaline accumulator of the nickel metal hydride type, comprising (I); and    (3) an alkaline accumulator of the nickel metal hydride type comprising the electrode.