Die flammenphotometrische Analyse (Atomabsorption) der Elemente Na, K, Mg, Mn und Ca im Zement

Ohne Zusammenfassung     

The synthesis of (+)- and (−)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylarsino)butane and their use in asymmetric catalysis

(+)- and (?)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylarsino)butane, the arsenic analogs of (+)- and (?)-diop have been synthesized in good yields. These ligands give similar optical yields to diop in the asymmetric hydrosilylation of ketones, but lower optical yields for the asymmetric hydrogenation of α-acetamidocinnamic acid, but, in this case, yield the isomer having the opposite configuration to diop.     

Polytypie bei Doppeloxiden: AgCoO2, AgFeO2, AgCrO2

Polytypes of AgFeO₂, AgCrO₂ and AgCoO₂ were found by indexing of high-resolution X-ray powder diagrams and, in the case of AgFeO₂ also by complementary single-crystal X-ray photographs. The abovementioned compounds occur at least in the polytype 6H (RAMSDELL-notation). The hexagonal unit cell dimensions are as follows: