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The article analyzes the green crystal structures of the inorganic compound trans-tetraamminedibromidochromium(III) trans-diamminetetrabromidochromate(III). It describes the coordination between the octahedral cations and anions of the compound through the interactions of nitrogen, hydrogen and bromide hydrogen bonds as well as its crystal packing showing a distorted CsCl-type lattice. It also considers the compound as the first real mixed ammine-acido chromiumIII cation-anion complex compound.

Green single crystals of trans-tetraamminedibromidochromium(III) trans-diamminetetrabromidochromate(III), [CrBr2(NH3)4][CrBr4(NH3)2], are found to contain two symmetry-independent sixfold coordinated Cr(III) cations on centres of inversion. The structure is composed of octahedral trans-[CrBr2(NH3)4]+ cations and octahedral trans-[CrBr4(NH3)2]- anions, and adopts a distorted CsCl-type lattice. The cations and anions are linked by N-H...Br interactions. This is the first example in which both ions are mixed ammine-bromide Cr(III) complexes.

Iron man challenge: Iron carbodiimide, FeNCN, and its precursor iron (bis)monohydrocyanamide, Fe(NCNH)(2), have been synthesized and physically characterized. Both FeNCN and Fe(NCNH)(2) exhibit nitrogen-mediated antiferromagnetic superexchange interactions with reduced magnetic moments very similar, but not identical, to the correlated 3d oxides.

Background and Aim of the Study: The study aim was to evaluate the relationship between serum calcium levels and the degree of calcification found in stenotic aortic valves., Methods: Using atomic absorption spectroscopy, the hydroxyapatite content of 228 excised human stenotic aortic valves was determined and expressed as a percentage of valve mass. Left heart catheterization preceded valve replacement. In addition, serum levels of calcium and creatinine were determined before native calcific aortic valve excision., Results: Valves from male patients contained more hydroxyapatite than those of female patients (26 +/- 9 versus 22 +/- 9 mass%; p < 0.001). Patients presenting with lower serum calcium levels showed a slight trend towards higher levels of valve calcification (r = -0.15, p = 0.026), but this association appeared only within the subgroup of male patients. Male patients with lowest serum calcium levels displayed greatest valvular hydroxyapatite deposition (1st calcium tertiary: 29.5 +/- 8.9 mass% versus 2nd calcium tertiary 26.4 +/- 7.8 mass% versus 3rd calcium tertiary 21.4 +/- 8.9 mass%; n = 122; p = 0.001; r = -0.25; p = 0.006). This association was even more distinct in male patients with normal serum creatinine levels. Furthermore, serum calcium was inversely and significantly associated with serum C-reactive protein in male patients (r = - 0.34; p < 0.001)., Conclusion: Serum calcium levels appear to be inversely related to valve calcification in patients with severe calcific aortic stenosis (AS). This finding indicates the importance of systemic calcium metabolism in calcific AS, independent of manifest disorders of calcium metabolism or renal function. Interestingly, this association was evident only in male patients, suggesting a gender-dependent pathogenesis.