Zirconium sulphides

5 Group 16 (chalcogen) compounds and complexes V.5.1 Sulphur compounds and complexes V.5.1.1 Zirconium sulphides 

A large number of zirconium sulphide compounds have been identified that range in composition from approximately Zr3S2 to ZrS3. The crystal structures of the compounds were studied in detail by Hahn et al. [57HAH/HAR] and are listed in Table V-26 together with their respective crystallographic data. 

From the measured heat contents of lMbS2(cr), TaS2(cr) and HfS2(cr), Volovik et al. [86VOL/KOV] estimated the high temperature heat content of ZrS2(cr) from 298 to 1600 K. Using the estimated values, they found that the variation in the heat content with temperature could be described by the equation  

Differentiating this equation with respeet to the temperature, [86VOL/KOV] obtained an expression for the heat eapacity of ZrS2(cr)  

Mills [74M1L] has reviewed and selected thermochemical data for solid metal sulphides, selenides and tellurides and estimated an entropy value for ZrS2(cr) of  

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Sulphur, Selenium, and Tellurium Compounds.—The crystal structure of the metal-rich zirconium sulphide Zr Sj has been determined and each sulphur atom shown to be at the centre of a square antiprism of zirconium atoms. The reaction of ZrS2 with potassium in liquid ammonia has been shown to give four K ZrS2 phases (.x = 1, 0.86, 0.71, or 0.71—0.22) which differ in the nature of the co-ordination sites occupied by the potassium atoms between the ZrS2 layers. ZrCl reacts with NaS2P(OEt)2 in toluene to form [Zr S2P-(OEt)2 4], which appears to involve a trigonal-dodecahedral arrangement of sulphur atoms about the metal. ... 

Table V-26 Stoichiometries and crystal structure parameters for zirconium sulphide compounds [57HAH/HAR]...

The thermochemical properties of zirconium sulphide compounds selected in this review are listed in Table V-27. 

Table V-27 8elected thermochemical properties of solid zirconium sulphide compounds at 298.15 K. The Gibbs energy of formation data are calculated from the selected enthalpies of formation and entropies.

Stoichiometries and crystal structure parameters for zirconium sulphide... 

The unit cell of a zirconium sulphide, with a measmed composition of 77Zr 100S, is of the halite (Bl) type, with oo = 0.514nm. The measured density is 4.80 x 10 kgm. Calculate the theoretical density of ideal ZrS with the Bl structure assuming that it contains either zirconium vacancies or sulphur interstitials, and give an opinion on the defect stmcture of the real material. 

Z 1 Niobium 1 Nitrate 1 Osmium 73 a. I Perchlorate Phenols u a o Platinum o 0. 1 5 u 1 Rhodium 1 Rubidium Ruthenium Scandium 1 Selenium Silver I Sodium 1 Strontium 1 Sulphate Sulphides, organic Sulphur dioxide 1 Tantalum 1 Tellurium 1 Thallium Thorium e H 1 Titanium a u ab a 1- I Uranium 1 Vanadium 1 Yttrium 1 Zinc Zirconium... 

Instead of lixiviating with water, the pyrosulphate fusion is followed in a recent process 7 by extraction with tartaric acid solution the insoluble residue contains silica, tin, and lead, and the solution, after being saturated with hydrogen sulphide for the precipitation of copper, antimony, etc., contains the hydroxides of niobium and tantalum as well as tungsten, titanium, zirconium, rare earth metals, etc. 

The dithizone method has been applied in determining cadmium in food products [12], natural waters [19], organic materials [76], zinc sulphide [23], beryllium [17], zirconium alloys [8], uranium compounds [77], Cd-Se and Cd-Te thin films [78]. The flow-injection technique (FIA) has also been applied in determining Cd with dithizone [79,80]. 

The existence of the zirconium selenides ZrSe(cr), ZrSe 5(cr), ZrSe2(cr), and ZrSc3(cr) have been reported. No experimental thermodynamic data are available except for ZrSesCcr) for which the heat capacity has been measured in the temperature range 8 to 200 K [86PRO/AYA]. These temperatures are too low for a derivation of thermodynamic quantities at 298.15 K. Mills [74MIL] has estimated some thermodynamic values by comparison with the corresponding sulphides and tellurides. 

In addition to the above, preparation in w/o microemulsions of nanoparticles of various other types of compounds, viz. silica-coated iron oxide, Fe203-Ag nanocomposite, oxides of ytrium, erbium, neodymium, vanadium and cobalt, titanates of barium and lead, ferrites of barium, strontium, manganese, cobalt and zinc, oxide superconductors, aluminates, zirconium silicate, barium tungstate, phosphates of calcium, aluminium and zinc, carbonates of calcium and barium, sulphides of molybdenum and sodium, selenides of cadmium and silver etc. have been reported. Preparative sources and related elaboration can be found in [24]. 

In Inorganic Chemistry, typical spray reagents for cations include potassium iodine (0.2%, aqueous), hydrogen sulphide (saturated aqueous solution), ammonium sulphide (0.2 N, aqueous), quercetin (0.1%, alcoholic), l-(2-pyridylazo)-2-naphthol (PAN) (0.2%, methanolic), oxine (8-hydroxyquinoline) (1% methanolic, view under visible and UV light), and sodium rhodizonate (0.5%, aqueous). Reaction with dithizone to produce coloured dithizonate chelates of many metals is particularly suitable if quantitative spectrometric analysis (in situ or after elution) is to be carried out. Anions are detected with bromocresol purple (0.1%, alcoholic), 1% ammoniacal silver nitrate + 0.1% alcoholic fluorescein/UV light, zirconium alizarin lake (0.1% in HC1 solution), and ammonium molybdate (1%, aqueous) followed by SnCl2 (1%) and HC1 (10%). Typical detection limits range from 10 ng (10 9g) to several pg (10 6g). 

Bear, J., McTaggart, F. K., The sulphides, selenides, and tellurides of titanium, zirconium, hafnium, and thorium. II. Chemical properties,... 

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