Ammonia complexes of hydroborates may be potentially promising materials for ammonia storage or indirect hydrogen storage. The title compounds contain 20,04-52.23 wt % ammonia and 5.94-13.01 wt % hydrogen. They were synthesized in liquid ammonia, using (NBu4)(2)[B12H12] and Li-2[B10H10] as starting materials. [Li-(NH3)(4)](2)[B12H12]center dot 2NH(3) (1) crystallizes in the monoclinic crystal system (space group P2(1)/c, a = 9.183(2) angstrom, b = 8.133(1) angstrom, c = 16.375 angstrom, beta = 110.54(1)degrees, V = 1143.97(40) angstrom(3), Z = 2). The compound is a direct precursor of the hydrogen storage compound Li-2[B12H12]center dot 7NH(3). Hydroborates of the heavier alkali metals were found to crystallize in the orthorhombic crystal system: Rb-2[B12H12]center dot 8NH(3) (2) (space group Pnnm, a = 14.4166(6) angstrom, b = 7.8221(3) angstrom, c = 9.5792(4) angstrom, V = 1080.23(8) angstrom(3), Z = 2), Cs-2[B12H12]center dot 6NH(3) (3) (space group Pbca, a = 7.7569(8) angstrom, b = 14.087(2) angstrom, c = 18.075(2) angstrom, V = 1974.99(30) angstrom(3), Z = 4), and Rb-2[B10H10]center dot 5NH(3) (4) (space group Pnma, a = 13.9510(7) angstrom, b = 8.675(2) angstrom, c = 13.966(2) angstrom, V= 1690.2(3) angstrom(3), Z = 4), as determined by single crystal X-ray diffraction. The structures are discussed briefly.