PROGRESS in the quantitative interpretation of the relative stabilities of metal complexes has been well maintained, and several important papers of a general nature have appeared during the year.A large volume of work on diborane and borohydrides, carried out about ten years ago, and awaited with much interest, has now been published. Some interesting new silicon hydrides have been prepared, e.g., S(SiH,), and P(SiH,),.There have been substantial developments in the chemistry of nitrogen, phosphorus, and sulphur, notably the discovery of the blue unstable compound " imine '' (NH), and the new allotropes, brown phosphorus and both purple and green sulphur; studies on the sulphur nitrides have progressed considerably and two new oxynitrides have been prepared.Progress in the chemistry of fluorine has included the preparation of interesting trifluoromethyl (CF,) derivatives of sulphur, phosphorus, and arsenic, and a new oxyfluoride of iodine (10,F).Greatly improved methods, using liquid ammonia, for the preparation of metal cyclopentadienyls have been used to obtain several new members of this particularly interesting class of compound. Carbonyls, which are now of much industrial importance, e.g., in connection with hydrof ormylation and carbonylation reactions, have received much attention, in particular the substitution of CO by other groups such as isocyanides, and the reactions between carbonyls and organic compounds.Review articles have been published during the year on stratospheric air,l the action of nitric acid on metals,, protactini~m,~ the stereochemistry of nickel and other simple inorganic compounds,7 and inorganic chromatography.s Accurate heats of formation have been obtained for the oxides of tin,g lanthanum, cerium,1° and hafnium,ll and vapour-pressure data for gallium metal,12 the iodides of boron and silicon,13 titanium tetrachloride l4 and uranium he~aflu0ride.l~ Other data are mentioned in later sections.Complexes.-A critical review of new and previously published data on the stability of complexes formed by bivalent ions of the first transition series has shown that the Irving-Williams order Mn < Fe < Co < Ni < Cu > Zn holds for nearly all such complexes irrespective of the nature of the co-ordinating ligand and even of the number of molecules involved. This seems to be a and hexacovalent complexe~,~ the thermochemistry of oxides
