Barium iron sulphides

The crystal structures of modulated materials can be illustrated by reference to the barium iron sulphides of formula BavFe2S4, and the similar strontium titanium sulphides, SrvTiS3. These phases fall into the sub-set of modulated structures called vernier structures, which have two interpenetrating chemical sub-structures. One of these expands or contracts as a smooth function of composition, while the other remains relatively... 

As in the case of the barium iron sulphides, the compositions of the (real or idealised) materials can be written as Sr ,(TiS3)lattice parameter of the complete structure, cs, is given by the least common multiple of the (-.-lattice parameters of the (more or less fixed) TiS3... 

Calculate the volume of 5 per cent barium chloride solution which must be added from the approximate sulphur content of the iron pyrites FeS2 or of the mineral sulphide. 

Ammonium sulphide) Barium sulphide Calcium sulphide Chromium (II) sulphide Copper (II) sulphide Diantimony trisulphide Dibismuth trisulphide Dicaesium selenide Dicerium trisulphide Digold trisulphide Europium (II) sulphide Germanium (II) sulphide Iron disulphide Iron (II) sulphide Manganese (II) sulphide Mercury (II) sulphide Molybdenum (IV) sulphide... 

With Barium Sulphide.—In the previous process which was considered, steam was decomposed by means of spongy iron in the present process, instead of iron, barium sulphide is used. If steam is passed over barium sulphide heated to a bright red heat, the following reaction takes place —... 

Pour the ferrate solution into three test tubes. Add a barium chloride solution to one tube up to complete precipitation. What is the composition of the precipitate Pour hydrogen sulphide water into the second tube, and 2 N sulphuric acid into the third one. What is observed Write the equations of all the reactions. What properties do iron(VI) compounds have ... 

Hydrogen sulphide is present in many mineral springs, and even free sulphur is occasionally found therein.2 Many metallic sulphides, for example, iron pyrites, galena, zinc blende, stibnitc and cinnabar, occur abundantly. Sulphur dioxide, sulphites, sulphuric acid and sulphates are also found in nature, more especially in waters springing from volcanic earth, whilst the sulphates of certain metals such as calcium, barium and magnesium exist in large deposits. 

Qualitative Analysis.—The minium is treated with dilute nitric acid effervescence indicates carbonates in the solution the lead is precipitated by means of hydrogen sulphide, the filtrate being tested for zinc, iron, aluminium, calcium and magnesium by the ordinary methods. The brown residue insoluble in nitric acid is heated further with nitric add in presence of either sugar solution or hydrogen peroxide until the lead dioxide is completely dissolved any insoluble residue then remaining may contain lead sulphate, barium sulphate or clay, which may be identified in the usual way. 

The barium carbonate is filtered off, and the liquor is concentrated so that it yields crystalline sodium sulphide Na. 9 H20 as a by-product. Barium sulphide can also be precipitated with carbon dioxide in a series of cast iron vessels. Barium carbonate, after it has been separated by filtration, is dried in a rotary dryer, heated by generator gas, and finally powdered in a rod mill. 

Double sulphides of iron and nickel are present in nickel matte, and are hence of commercial importance. Double sulphides with potassium, K2S.3NiS, and barium, BaS.4NiS, may be obtained by fusing nickel, sulphur, and an alkali at a high temperature.8 They are crystalline compounds. Cobalt yields only the sesquisulphide, Co2S3, in like circumstances. Nickel thus resembles palladium and platinum, whilst cobalt resembles rhodium and iridium in these respects. The position of nickel after cobalt in the Periodic Table thus receives further justification. 

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