
%0 Journal Article
%A Waters, AF 
%A White, AH 
%T Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. I. Some Adducts of Group 2 Halides With Acetonitrile
%J Australian Journal of Chemistry
%D 1996/01/01
%V 49
%N 1
%P 27-34
%K 
%R https://doi.org/10.1071/CH9960027
%U https://www.publish.csiro.au/paper/CH9960027 
%X Recrystallization of anhydrous Group 2 halides from anhydrous acetonitrile has yielded, in a number of cases, adducts MX2.nMeCN suitable for characterization by room-temperature single-crystal X-ray    studies, which revealed novel stereochemical types. Magnesium(II) bromide yields a trisolvate, ionic with disproportionated ligand arrays, as [Mg(NCMe)6][MgBr4] (1), an unusual combination of homoleptic cationic and anionic species. Crystals are triclinic,  P&#299; , a 19.129(1), b l6.870(8), c 8.737(7) &#506;,&#945; 83.96(3), &#946; 87.93(4), &#947; 65.24(2)°, Z=4 f.u .; R was 0.068 for N o  3181 'observed' (I > 3&#963;(I)) reflections. Mg-N are 2.12(2)-2.18(2) &#506;, and Mg-Br are 2.452(7)-2.481(6) &#506;. Calcium(II) bromide, by contrast, yields a disolvate , an infinite polymer, with the two MeCN  ligands trans in a quasi-octahedral coordination sphere, and the polymer comprising a ... Ca(&#956;-Br)2Ca(&#956;-Br)2... linear array. Crystals of 1:2 CaBr2/MeCN (2) are orthorhombic, Pbam , a l4.252(3), b 8.539(2), c 4.2088(6) &#506;, Z=2 f.u .; R 0.043 for N  o 352. Ca-N is 2.46(1) &#506;, and Ca-Br 2.8765(9) &#506;. CaI2 and SrI2 yield pentasolvates as neutral, molecular species [( MeCN )5MX2] (3) and (4), with the halides trans in a pentagonal bipyramidal coordination sphere. They are isomorphous . orthorhombic, Pcab , a &#8776; 18.4, b &#8776; 14.6, c &#8776; 14.3 &#506;, Z = 8 f.u .; R were 0.042 and 0.059 for N o  2297 and 1489 respectively. Ca-I are 3.132(2), 3.116(2) &#506; and Sr -I are 3.265(3), 3.238(3) &#506;, while Ca-N are (range) 2.518(8)-2.566(8) &#506; and Sr -N 2.68(2)-2.73(2) &#506;. 
