A new thiazolylimine ligand system for iron(ii) complexes which stabilises spin-crossover in solution and solid states with T1/2 temperatures around room temperature has been developed. This effect is studied in solution and solid states. Furthermore crystal packing effects are investigated offering a variety of T1/2 and even hysteresis centred at -3 °C in the solid state.

Dedicated to Professor Caroline Röhr on the Occasion of Her 60 th BirthdayThe reaction of elemental barium, gallium and either bismuth or antimony with small amounts of barium peroxide yields yellow platelet-shaped crystals of Ba 9 [GaO 4 ] 3 Sb (1) and orange platelet-shaped crystals of Ba 9 [GaO 4 ] 3 Bi (2), respectively. Using arsenic instead of bismuth or antimony, black metallic shining crystals of Ba 2 [GaO 2 As] (3) are obtained. The crystals of these compounds are air-sensitive and have been characterized by single crystal X-ray diffraction and energy dispersive X-ray fluorescence spectroscopy. 1 and 2 contain tetrahedral [GaO 4 ] 5À units and isolated Sb 3À and Bi 3À ions coordinated solely by Ba 2 + -ions in icosahedral and cuboctahedral fashion. 3 is built of [GaO 2 As 2/2 ] 4À tetrahedra, which are linked via the As atoms to infinite chains. This polyanion can be perceived as a typical Zintl anion, which is partially oxidized.

The cover picture shows a section of the the chain of connected GaO2As2 tetrahedra in the crystal of Ba2[GaO2As] and the coordination polyhedron of the As atom by surrounding Ba ions. This [–O2Ga–As–4−]n polyanion reminds of a typical Zintl phase with covalent triele–pnictide bonds in the infinite Ga–As chain. The incorporation of oxygen bound to a constituent of the polyanion is a rare and unique structural feature. One can perceive this compound as a Zintl phase with a partially oxidized polyanion. S. Klos et al. describe in their article the access to a new class of metallate‐metallides in the system Ba/Ga/Pn/O (Pn=As, Sb, Bi) by adding sub‐stochiometric amounts of BaO2 as the oxygen source to mixtures of Ba, Ga, and one of the pnictide elements. With the heavier pnictides Sb and Bi, Ba9[GaO4]3Pn is formed with a different structure type containing oxogallate anions [GaO4]5− encapsulating discrete Sb3− and Bi3− ions. (DOI: 10.1002/zaac.202100363).