Square antiprism geometry

Figure 9.28 (a) Points-on-a-sphere model of a square an-liprism. (b) The square antiprism geometry of the IFg2- ion. 

Bi-0 2.54(l)-2.68(2) A], In contrast, the nine-coordinate capped square antiprism geometry for bismuth in [Bi(N03)3(H20)3] (18-crown-6) does not involve the expected multidentate ether coordination to bismuth, but rather a hydrogen-bonded interaction of the crown ether with the hydrated bismuth center chelated by bidentate nitrate groups [Bi-0 2.38(2)—2.56(2) A] 32, implying that the hexado-... 

The H nmr spectrum of Zr(Hf)(acac)4 in CHCIF2 shows two Me proton resonances of equal intensity in the slow exchange region only at lowered temperature ( —170°Ci). This observation is consistent with a square antiprism geometry 11. At — 145°C coalescence of the signals occurs arising from complicated intramolecular rearrangements. 

Lu(H20)4(al-P2Wi706i)] is an example of 1 1 complexes of RE with [al-P2Wi706i] ° . In this complex, the lutetium ion is eight-coordinated in a square-antiprism geometry with four oxygen atoms surrounding the vacant site and four water molecules [12],... 

Ho5(H20)i6(OH)2As6W64022o] is a linear cluster composed of six [B-a-AsW9033] fragments linked by a [Ho5Wio(H20)i6(OH)2022] belt. The five holmium atoms are eight-coordinated with a square-antiprism geometry [43]. 

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