TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Properties: The composition has a unit cell volume of 87-88.5 Angstrom3 and a plateau pressure of 1-60 psi at 25 degreesC. Preferably the plateau pressure is 3-10 psi. The alloy is isothermally heated at 900-1100 degreesC for 2-24 hours.Preferred Composition: The alloy contains 6000 or less ppm of at least one element selected from lead, carbon, nitrogen, oxygen, fluorine, chlorine, sulfur and phosphorus. Preferred Definitions:    R = lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium or yttrium, preferably lanthanum, cerium, praseodymium, neodymium or samarium, most preferably lanthanum;    M = titanium, vanadium, chromium, zirconium, niobium, hafnium, tantalum or tungsten;    In (I), u = 0-0.15, preferably 0.01-0.2, most preferably 0.05-0.2;    v = 0-0.06, preferably 0.001-0.05, most preferably 0.02-0.04;    w = 0.005-0.03, preferably 0.01-0.03, most preferably 0.01-0.02; and    z = 4.9-5.35, most preferably 5-5.15.    In (II), u = 0-0.8025, preferably 0.0485-1.09 most preferably 0.245-1.04;    v = 0-0.321, preferably 0.00485-0.2725, most preferably 0.098-0.208;    w = 0.0245-0.1605, preferably 0.0485-0.1635, most preferably 0.049-0.104; and    z = 4.90-5.35, preferably 4.9-5.2, most preferably 5-5.15    SPECIFIC COMPOUNDS - Examples of the alloy composition are (La0.62Ce0.26Nd0.09Pr0.03) (Al0.03Cr0.01Co0.15Ni0.86)5.1, La(Al0.03Cr0.01Co0.15Ni0.81)5.1, La(Co0.10Al0.03Cr0.01Ni0.86)5.1 and (La0.64Ce0.26Nd0.08Pr0.03) (Co0.10Al0.03Cr0.01Ni0.86)5.    EXAMPLE - An alloy of La(Co0.1Al0.03CrxNiy)5, where x = 0.01 and y = balance and a control alloy of (La0.32Ce0.49Nd0.14Pr0.04) (Co0.12Al0.06Mn0.1Ni0.72)5.1 were prepared by vacuum induction melting and mold casting. The unit cell volume of the alloy was 87.618 Angstrom3 and that of control alloy was 88.31 Angstrom3, determined by X-ray diffraction. The plateau pressure was 7.2 psi and that of control was 1.5. The discharging capacity at 50, 500 and 1000 mA/g electrochemical test were 380, 375 and 350 mA/g respectively compared with 340, 75 and 50 mA/g respectively for the control. The ratio of C1000/C50 was 0.92 while that of the control sample was 0.15.