Vacuum stable

Lubricants. TeUurides of titanium, 2irconium, molybdenum, tungsten, and other refractory metals are heat- and vacuum-stable. This property makes them useful in soUd self-lubricating composites in the electronics, instmmentation, and aerospace fields (see Lubrication and lubricants). Organic teUurides are antioxidants in lubricating oUs and greases. 

Alternatively wash with water, then with 1 % NaOH or 5% Na2C03 for several hours, then finally with water. Dry under reduced pressure and fractionate carefully under vacuum. Stable colourless oil, sparingly soluble in H2O (ImL dissolves in 165mL of H2O), but freely miscible in organic solvents. [J Am Chem Soc 74 4953 1952, 80 5441 795S 3>P NMR J Am Chem Soc 78 5715 1956 J Chem Soc 1488 1957.]... 

The plasma ionic liquid interface is interesting from both the fundamental and the practical point of view. From the more fundamental point of view, this interface allows direct reactions between free electrons from the gas phase without side reactions - once inert gases are used for the plasma generation. From the practical point of view, ionic liquids are vacuum-stable electrolytes that can favorably be used as solvents for compounds to be reduced or oxidised by plasmas. Plasma cathodic reduction may be used as a novel method for the generation of metal or semiconductor particles, if degradation reactions of the ionic liquid can be suppressed sufficiently. Plasma anodic oxidation with ionic liquids has yet to be explored. In this case the ionic liquid is cathodically polarized causing an enhanced plasma ion bombardment, that leads to secondary electron emission and fast decomposition of the ionic liquid. 

N02 GeF5". NO2F and Gep4 were mixed at room temperature in equiminfrared spectra as an N02 salt. 

The first tasks of the work described in this paper were to define the chemical compositions of the vacuum-stable products derived from the interaction of graphite with AsF, AsF, mixed with F2, and OjAsF,. The second tasks were to explain the peculiar features of the X-ray powder diffraction (XRPD) pattern for the stage-one C,4AsF, (/, a 7.6 A). A novel structure involving fluoride ligand nestling of the AsF," in the hexagonal depressions of the carbon atom sheets is proposed. 

The X-ray arsenic K-shell pre-absorption edge feature [As(ls— 4p) transition] for the vacuum-stable product, ca. CigAsF, prepared from graphite and AsFj followed by evacuation, gave the single peak feature shown in Fig. 3, and indicates that AsF is the sole guest species in a vacuum-stable sample. This contrasts with the double peak feature reported by Bartlett et al. ° for the material from which volatiles had not been removed, and which was characteristic of a mixture of AsFj and AsF species. 

Table 1 Analytical data and I, distances for the vacuum-stable solid products obtained from (1) graphite -E AsF,. (2) graphite + AsF, + F, and (3) graphite + OjAsF ...

A) (i ll) the limit of x in C Asp appears to be ca. 10. Although Fig. 5 does not show it, the composition of the pure stage-two material, in which the other stage phases were not detectable by XRPD, was ca. C sAsP ,. These observations indicate that the vacuum stable C(,AsF salts with the 4 distance of ca. 7.6 -F3.35n A have the staging formula Ci AsFj. 

Nestled Salts. A more dramatic instance of the effect of dielectric spacers in graphite salts is provided (32) by the first-stage fluoroarsenate of composition C14ASF6. This material is prepared by the routes shown in Scheme I and is identical to the first-stage component of the vacuum-stable... 

Intercalation of graphite by SiF4 in the presence of F2 has been achieved and a vacuum stable second-stage salt of composition C24SiF5 appears to represent the intercalation limit. This paper describes its preparation and some of its properties. 

A vacuum-stable first-stage hexafluorophosphate of approximate composition CnPFg was prepared by treating graphite (typically 10.5 mm mol) with PF5 and F2 (400 and 300 torr respectively as measured in the line) at 20° for 12 hours. Volatiles were removed in a dynamic vacuum. The vacuum-stable residual solid (PF uptake 0.95 mm mol) proved to be a first-stage compound, with Oq = 2.46(1), Cq = 7.79(3) A, carbon analysis of which gave C = 47.3% (C = 47.7% is required for CuPFg). 

More fluorine generates the vacuum stable first-stage compound CnPFg. 

Properties Gray-black solid. Mp >1316C, vacuum stable from -430 to 2400F (-170 to 1315C). Has higher electrical conductivity than graphite. 

Successful MALDI analysis is dependent on a number of factors, not the least of which is selection of an appropriate matrix. The matrix must be soluble in solvents compatible with the analyte (usually an aqueous/ organic solvent mixture) and it must be possible to cocrystallize the analyte and matrix onto the target. The matrix must also be vacuum stable and be able to absorb at the emission wavelength of the laser. In addition, it must be able to cause codesorption of the analyte and promote analyte ionization. See Table 2 for a list of commonly used MALDI matrices. 

If the sample is of a liquid form under standard temperatnre and pressure conditions, they must be converted into a solid form that will be vacuum stable. This is generally accomplished through freeze-drying procedures covered in Section 5.2.3. 

Curing for a sufficient time (overnight) such that these become sufficiently vacuum stable... 

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