Compounds of silicon and homologues, 134. Supersilyl compounds of boron and homologues, 10. Tri(supersilyl)dialanyl (tBu3Si)3Al2· and tetra(supersilyl)cyclotrialanyl (tBu3Si)4Al3· - new stable radicals of a group 13 element from thermolysis of (tBu3Si)4Al2. European Journal of Inorganic Chemistry, 7:1475--1481, 2000. [PUMA: ESR aluminum decompn prepn radical radical;supersilyl silyl silyldialuminum structure structure;crystal structure;thermal trinuclear]