A simple method was developed for the laboratory preparation of gradient columns of specific gravity used in measurement of brain-tissue water. By this automated technique, virtually linear and repeatable density gradients were obtained from which values of tissue specific gravity could be determined. The specific gravity of both solid and fresh cortex and white matter from adult cats was measured and converted to units of percent water per gram tissue using conversion factors derived for this purpose and applicable to studies of brain edema.

No abstract

Lithium‐tris(trimethylsilyl)silanid · 1,5 DME [3] reagiert mit Tellur in 1,2‐Dimethoxyethan zu farblosem Lithium‐[tris(trimethylsilyl)silyi]tellanid · DME (1). Nach der Röntgenstrukturanalyse {‐150 ± 3°C; P21/c; a = 1346,6(4); b = 1497,0(4); c = 1274,5(3) pm; β = 99,22(2)°; Z = 2 Dimere; R = 0,030} ist Verbindung 1 im Festkörper dimer; die beiden Tris(trimethylsilyl)silyl‐Gruppen sind am planaren LiTeLiTe‐Ring trans‐ständig zueinander angeordnet. Tellur erreicht durch Bindung an zwei Lithium und ein Silicium die Koordinationszahl 3, Lithium durch Bindung an zwei Tellur und den Chelatliganden DME die Koordinationszahl 4 {LiTe 278 und 284; SiTe 250; LiO 200 pm (2X); TeLiTe 105°, LiTeLi 75°; OLiO 84°}. Der hier zu 154 pm ermittelte kovalente Radius des DME‐komplexierten Lithiumatoms fällt in den auch für andere Verbindungen typischen Bereich von 155 ± 3 pm. Charakteristische Umsetzungen des Tellanids 1 führen zu [Tris(trimethylsilyl)silyl]tellan (2), Methyl‐[tris(trimethylsilyl)silyl]tellan (4) und Bis[tris(trimethylsilyl)silyl]ditellan (5).

In acetonitrile solution HOF oxides CF3SSCF3 via With CH3CN at low temperatures HOF and HF form 1 : 1 ad-CF3S(0),SCF3 (n = 1, 2) to yield [CF3S(0)2]20. Analogously, ducts, whose structures have been elucidated by low-tem-CF,Se(O)OH and CF,SeX (X= C1, Br) are oxidized via perature X-ray structure analysis. Additional proof for the CF,Se(VI) intermediates to provide finally [CF,Se(O),],O. formation of CH3CN . HF in the liquid phase is provided.

Z 700 IE] German version: Angew. Chem. 96 (1984) 367 Angew. Chem. Int. Ed. Engl. 23 (1984) No. 5 0 Verlag Chemie GmhH, 0-6940 Weinheirn, 1984 0570-0833/84/0.505-0389 $02.50/0