Hanne Nuss

The crystal structures of solvent-free alkali-metal squarates from powder diffraction data

Abstract The crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li2C4O4: a = 7.1073(3) Å, b = 9.5627(4) Å, c = 3.2973(1) Å, β = 101.11(1)°, V = 219.91(1) Å3, monoclinic, C2/m, Z = 2, Na2C4O4: a = 3.4925(1) Å, b = 6.8152(1) Å, c = 10.3525(2) Å, β = 91.56(1)° V = 246.32(1) Å3, monoclinic, P21/c, Z = 2; Rb2C4O4: a = 10.7908(5) Å, b = 6.8494(3) Å, c = 4.4521(2) Å, β = 92.39(0), V = 328.77(4) Å3, monoclinic, C2/m, Z = 2; Cs2C4O4: a = 11.1768(3) Å, b = 7.0453(2) Å, c = 4.7424(1) Å, β = 92.89(1)°; V = 372.97(4) Å3, monoclinic, C2/m, Z = 2. The packing features of lithium squarate can be deduced from the AlB2 structure type, while sodium, rubidium, and cesium squarate are related to the CdI2 type. The relation between the two types of crystal structures of the squarate dianion is discussed.

Synthese und Kristallstrukturbestimmung von Cs([18]Krone-6)Au · 8NH3/ Synthesis and Crystal Structure Determination of Cs([18]crown-6)Au· 8NH3

Cs([18]crown-6)Au ・ 8NH3 was synthesized from CsAu and [18]crown-6 in liquid ammonia. The extremely air- and temperature-sensitive colorless, block-shaped crystals were analyzed by single crystal X-ray diffractometry. The compound forms triclinic crystals of space group P1 (no. 1) with a = 8.765(2), b = 11.186(2), c = 13.997(3) Å , α = 86.180(6), β = 89.669(6), γ = 83.774(6)°, V = 1361.2(4) Å3. The crystal structure consists of ammonia nets extending perpendicular to [110] in which the Cs([18]crown-6) fragments and the auride anions are embedded

Synthesis and Crystal Structure of M([12]crown-4)2O3 · 1.5 NH3 with M = K, Rb

The two new ozonide compounds K([12]crown-4)2O3 ・ 1.5 NH3 (1) and Rb([12]crown-4)2O3 ・ 1.5 NH3 (2) were synthesized from the binary alkali metal ozonides and [12]crown-4 in liquid ammonia. The air- and temperature-sensitive red, needle-shaped compounds crystallize isostructurally in the non-centrosymmetric space group Fdd2 (no. 43) with 16 formula units per unit cell. The lattice parameters are a = 26.917(8), b = 43.25(1), c = 7.823(2) Å, V = 9108(5) Å3; and a = 26.730(6), b = 44.70(1), c = 7.739(2) Å, V = 9245(4) Å3 for 1 and 2, respectively. The structure comprises rod-like [([M([12]crown-4)2(NH3)]O3)2(NH3)] supramolecular units, forming a fishbone pattern parallel to (001). The ozonide anions are separated from the metal cations and interact only weakly with two ammonia molecules via N-H・ ・ ・O hydrogen bonds Graphical Abstract Synthesis and Crystal Structure of M([12]crown-4)2O3 · 1.5 NH3 with M = K, Rb