Titanium disulfide

The following procedure describes the synthesis of the most stoichiometric and thoroughly characterized TiS2 prepared to date by direct reaction of the 

All glassware and fused silica ampules associated with the synthesis are cleaned using a cleaning solution consisting of 4S mL of 48% HF, 165 mL of concentrated HNO3, 200 mL of HjO, and 10 g of Alconox detergent. 

After a 3-min exposure to the cleaning solution, the glassware or fused silica ampules are rinsed at least 25 times with distilled water and subsequently rinsed five additional times with MQ-cm water that has been filtered to remove organic contaminants. The glassware or fused silica ampules are then dried at 110°. 

The first reaction step involves adding stoichiometric amounts of Ti and S (99.9995%) (Alfa Products), with an extra 5 mg/cm S, to a 12-mm-o.d. fused silica ampule having a 1-mm wall thickness. (Care should be taken to avoid 

The excess S is vapor transported to the opposite end of the ampule from the disulfide using a 325 + 25°-to-ambient temperature gradient. The ampule is left in the gradient for 1-2 h, removed, allowed to cool, and its TiSj is gently agitated. The ampule is then replaced in the gradient. After an additional 1 -2 h, the ampule is removed and allowed to cool to ambient temperature. 

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Titanium carbide may also be made by the reaction at high temperature of titanium with carbon titanium tetrachloride with organic compounds such as methane, chloroform, or poly(vinyl chloride) titanium disulfide [12039-13-3] with carbon organotitanates with carbon precursor polymers (31) and titanium tetrachloride with hydrogen and carbon monoxide. Much of this work is directed toward the production of ultrafine (<1 jim) powders. The reaction of titanium tetrachloride with a hydrocarbon-hydrogen mixture at ca 1000°C is used for the chemical vapor deposition (CVD) of thin carbide films used in wear-resistant coatings. 

Titanium Dichloride. Titanium dichloride [10049-06-6] is a black crystalline soHd (mp > 1035 at 10°C, bp > 1500 at 40°C, density 31(40) kg/m ). Initial reports that the titanium atoms occupy alternate layers of octahedral interstices between hexagonaHy close-packed chlorines (analogous to titanium disulfide) have been disputed (120). TiCl2 reacts vigorously with water to form a solution of titanium trichloride andUberate hydrogen. The dichloride is difficult to obtain pure because it slowly disproportionates. 

Titanium disulfide can also be made by pyrolysis of titanium trisulfide at 550°C. A continuous process based on the reaction between titanium tetrachloride vapor and dry, oxygen-free hydrogen sulfide has been developed at pilot scale (173). The preheated reactants ate fed iato a tubular reactor at approximately 500°C. The product particles comprise orthogonally intersecting hexagonal plates or plate segments and have a relatively high surface area (>4 /g), quite different from the flat platelets produced from the reaction between titanium metal and sulfur vapor. The powder, reported to be stable to... 

The principal use of titanium sulfides is as a cathode material ia high efficieacy batteries (11). In these appHcations, the titanium disulfide acts as a host material for various alkafl or alkaline-earth elements. 

Titanium disulfide has been proposed as a soHd lubricant. The coefficient of friction between steel surfaces is 0.3, compared to only 0.2 for molybdenum disulfide. However, because it does not adhere strongly to metal surfaces, TiS2 is generally less effective than molybdenum sulfide. 

Dioxolane-l, 2-dimethoxyethane-Li2 B1()C11() exhibited chemical stability towards the components of a lithium-titanium disulfide cell and showed promise as an electrolyte in such cells [98], Among various systems composed of an ether-based solvent and a lithium salt, THF-LiAsF6 was the least reactive to lithium at elevated temperature and gave the best cycling efficiency [99, 100], Tetrahydrofu-ran-diethyl ether-LiAsF(i afforded lithium electrode cycling efficiency in excess of 98% [101],... 

Mixtures of potassium nitrate with antimony trisulfide [1], barium sulfide, calcium sulfide, germanium monosulfide or titanium disulfide all explode on heating [2]. The mixture with arsenic disulfide is detonable, and addition of sulfur gives a pyrotechnic composition [2], Mixtures with molybdenum disulfide are also detonable [3], Interaction with sulfides in molten mixtures is violent [4],... 

This defect is therefore neutral in terms of effective charge. The same could be said of a neutral lithium atom introduced into an interstitial site in titanium disulfide, TiS2, which would be written Lip However, it is sometimes important to emphasize that the defect is neutral in terms of effective charge. This is made clear by the use of a superscript x. Thus a K+ ion substituted for a Na+ ion could be written K a when the effective charge situation needs to be specified. Similarly, an interstitial Li atom could be represented as Lif to emphasize the lack of an effective charge on the defect when it is essential to do so. 

Titanium disulfide, 25 57, 58 Titanium disulfide electrodes sloping discharge curve, 3 414 Titanium esters, 25 1 Titanium fluorides, 25 47-49 Titanium halides, 25 47-55 Titanium hydride, 13 626 Titanium hydrides, 25 5 Titanium-hydrogen system, 25 3-5 phase diagram for, 25 5 Titanium iodides, 25 54-55 Titanium/isopropoxy/nitrilotriethoxy ratio, 25 93... 

The ready reversibility of lithium in titanium disulfide has permitted deep cycling for close to 1000 cycles with minimal capacity loss, less than 0.05% per cycle, with excess lithium anodes. Exxon marketed button cells with LiAl anodes and TiS2 cathodes for watches and other small devices in 1977—1979 the LiAl anode improved the safety of the cells. Some of the largest lithium single cells built to date are those exhibited by Exxon at the Electric Vehicle Show in Chicago in 1977, shown in Eigure 3. 

Figure 5. Synthesis approaches for titanium disulfide, after ref 46.

Figure 6. Reaction of n-butyllithium with titanium disulfide, vanadium pent oxide, and molybdenum trioxide (reprinted with permission from ref 77, copyright 1977 The Electrochemical Society).

Titanium disulfide has a Cdl2 structure (see Chapter 1). The solid is golden-yellow and has a high electrical conductivity along the titanium layers. Forming intercalation compounds with electron donors can increase the conductivity of titanium disulfide, the best example being with lithium, LLTiS2. This compound is synthesized in the cathode... 

Whittingham in the seventies developed a battery that operated at room temperature based on the intercalation of Li in TiS2. In the lithium/titanium disulfide battery, one electrode is lithium metal and the other is titanium disulfide bonded to a polymer such as teflon. The electrolyte is a lithium salt dissolved in an organic solvent. Typically, the... 

When the circuit is complete, lithium metal from the lithium electrode dissolves giving solvated ions, and solvated ions in the solution are deposited in the titanium disulfide. These ions intercalate into the disulfide, and electrons from the external circuit balance the charge. Thus, the two electrode reactions are ... 

A number of nearly two-dimensional intercalates of formula [MY2(L)X] (Y = S, Se L = N donors x = 0.5 for L = py, Et2NH, Et3N, piperdine, etc.) with promising superconducting properties have been described.573 Niobium disulfide is an intercalation electrode in lithium batteries, whose effectiveness is close to that of titanium disulfide.574... 

Metal sulfides MRH Antimony trisulfide 2.30/37, titanium disulfide 3.42/26... 

Mixtures of potassium nitrate with antimony trisulfide [1], barium sulfide, calcium sulfide, germanium monosulfide or titanium disulfide all explode on heating [2]. The... 

Metal Sulfides. Mixtures with antimony trisulfide, barium or calcium sulfides, or germanium monosulfide or titanium disulfide explode on heating4-6 mixtures with arsenic disulfide6 or molybdenum disulfide7 are detonatable. 

The sulfides of titanium are, in this connection, of particular interest. Inasmuch as TiS crystallizes with the NiAs structure and TiS2 with the Cdl2 structure, the existence of an intermediate compound of the sesquisulfide type has long been the object of speculation (I, 3), until the last few years when its existence has been definitely established (4, 5,9). For our part, we have concentrated our attention on titanium disulfide, titanium sesquisulfide, and the manner of transition from one to the other. 

Crystals of titanium disulfide occur in the form of golden hexagonal plates with an extremely marked metallic luster. If the reaction tube does not contain enough sulfur to give a S/Ti ratio of 2, a powdery compound will be formed which has the same unit cell as the stoichiometric sulfide, but which maintains a S/Ti ratio of less than 2. 

We have not studied sulfides of higher titanium content than those constituting the Ti2S3 phase. We concentrated on determining the nature of the defects responsible for the deviations from stoichiometry that can occur in titanium disulfide. Next, we inquired into the alteration of the structure of this system as titanium is inserted. This led us to encounter a whole series of complex forms, in the nature of superlattices, which account for the transition between TiS2 and Ti2S3. To make the study complete, it would be necessary also to determine the conditions required for the transition from Ti2S3 to TiS, and to elucidate in particular the structure of the compound which occurs between these two phases. 

Titanium disulfide, like the disulfides of Zr, Hf, V, Nb, and Ta, has a layer structure two adjacent close-packed layers of S atoms have Ti atoms in octahedral interstices. These sandwiches are then stacked so that there are adjacent layers of S atoms. Lewis bases such as aliphatic amines can be intercalated between these adjacent sulfur layers similar intercalation compounds can be made with M and MSe2 compounds for M = Ti, Zr, Hf, V, Nb, and Ta. Many of these have potentially useful electrical properties, including use as cathode material for lithium batteries, and superconductivity, and may be compared with the intercalation compounds of... 

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