No abstract

Zn(CHaCHOHCOO)2.3H20 is monoclinic, space group P21/c, with a=9"38, b=5-83, c=22-00 /~; ,6= 90.9 °, Z= 4. The structure was solved by Patterson and Fourier methods and refined by full-matrix least-squares calculations to a final R of 0"105 for 1434 visual reflexions. The molecular dimensions are normal. The corresponding bond lengths in the bidendate lactate groups agree well with each other. Six oxygen atoms, four from lactate groups and two from water molecules, form a distorted octahedron round the zinc atom. The average Zn-O distance is 2.11 A,. All three water molecules take part in hydrogen-bond formation.

Coordination complexes between dinitriles of dicarboxylic acids and tetrahalides of titanium, zirconium, or tin have been prepared. The analytical results and the infrared spectra indicate that on working under different experimental conditions three types of compounds are obtained: 2MX4.L-L, MX4.L-L, and MX1.2L-L where M X 4 is a Lewis acid and L-L a bidentate ligand. The compounds 2MXd.L-L are explained by the formation of halogen bridging between the two metal atoms. The compounds MX4.L-L are considered to be either coordination polymers or chelates of variable ring size and the compounds MX4.2L-L, ordinary addition compounds where no chelation takes place because of the mutual interaction of the two CN groups in a dinitrile of a short chain length.

J ournal type of study is carried out on barium borosilicate glasses containing only uranium ions.

Coordination complexes between α-cyanoacetamide as ligand and the group (IV) halides as Lewis acids have been prepared. In all these compounds the ligand has been found to be a bidentate, coordinating to two different metal atoms. The infrared results indicate coordination through the nitrogen of the cyano group and one of the donor atoms of the amide group, probably nitrogen. Some physical properties of the complexes strongly suggest that they are coordination polymers.