Sodium oxide coordination number

Chromium (II) also forms sulfides and oxides. Chromium (II) oxide [12018-00-7], CrO, has two forms a black pyrophoric powder produced from the action of nitric acid on chromium amalgam, and a hexagonal brown-red crystal made from reduction of Cr202 by hydrogen ia molten sodium fluoride (32). Chromium (II) sulfide [12018-06-3], CrS, can be prepared upon heating equimolar quantities of pure Cr metal and pure S ia a small, evacuated, sealed quartz tube at 1000°C for at least 24 hours. The reaction is not quantitative (33). The sulfide has a coordination number of six and displays a distorted octahedral geometry (34). 

The oxidation of 1,2-glycols by sodium periodate or periodic acid generally is considered to proceed by way of an intermediate complex between the periodate ion and the glycol.84 Studies by Duke and Bremer26 of the reaction kinetics support the hypothesis that the periodate ion reacts with a coordination number of two and that the reacting complex is exclusively between one mole of glycol and one periodate ion. 

The oxides and acids of antimony resemble those of arsenic, except that antimony in antimonic acid has coordination number 6, the formula of antimonic acid being HSb(OH)3. A solution of potassium antimonate, K+[Sb(OH)g], finds use as a test reagent for sodium ion sodium antimonate, NaSb(OH)3, one of the very few sodium salts with slight solubility in water (about 0.03 g per 100 g), is precipitated. The. antimonate ion condenses to larger complexes when heated this condensation may ultimately lead to macromolecular structures, such as... 

Inorganic cyanides have been studied both as simple salts and as coordination complexes. Rao et al. [55] have listed data on the former, as have El Sayed and Sheline [56], and Nakamoto has given a table of a very large number of frequencies for coordination compounds [46]. The frequencies depend upon the electronegativity, oxidation number and coordination number of the atom to which the C=N group is attached [56]. In salts such as sodium... 

The oxidation-number system is easily extended to include other coordination compounds. Even the interesting substances represented by the formulas Na4Ni(CN)4 and K4Pd(CN)4 create no nomenclature problem they become sodium tetracyanonickelate(0) and potassium tetracyanopaHadate(0), respectively. 

---