Wollaston

Figure Bl.18.8. Differential interferenee eontrast the light beam is split into two beams by a Wollaston prism. The two beams pass the objeet at elosely spaeed positions and give, after interferenee, a eontrast due to the phase differenee.

Gr. rhodon, rose) Wollaston discovered rhodium in 1803-4 in crude platinum ore he presumably obtained from South America. 

Discovered in 1803 by Wollaston, Palladium is found with platinum and other metals of the platinum group in placer deposits of Russia, South America, North America, Ethiopia, and Australia. It is also found associated with the nickel-copper deposits of South Africa and Ontario. Palladium s separation from the platinum metals depends upon the type of ore in which it is found. 

Frenchman P. F. Chabeneau, and subsequently in London by W. H. Wollaston/ who in the years 1800-21 produced well over 1 tonne of malleable platinum. These techniques were developed because the chemical methods used to isolate the metal produced an easily powdered spongy precipitate. Not until the availability, half a century later, of furnaces capable of sustaining sufficiently high temperatures was easily workable, fused platinum commercially available. 

In 1803, in the course of his study of platinum, Wollaston isolated and identified palladium from the mother liquor remaining after platinum had been precipitated as (NH4)2PtCl6 from its solution in aqua regia. He named it after the newly discovered asteroid, Pallas, itself named after the Greek goddess of wisdom (ytaXXd iov, palladion, of Pallas). 

Platinum in the forms detailed above and in its more usual alloys with other noble metals is available as sheet, foil down to 0-0064 mm thick, tube, rod, wire down to 0-0064 mm diameter, Wollaston wire down to 0-001 mm diameter, and clad on thin sections of base metals, e.g. copper, nickel. Inconel, etc. 

Historically, the visible emission lines shown in Figure 15-3 were the first atomic hydrogen lines discovered. They were found in the spectrum of the sun by W. H. Wollaston in 1802. In 1862, A. J. Angstrom announced that there must be hydrogen in the solar atmosphere. These lines were detected first because of the lesser experimental difficulties in the visible spectral region. They are called the "Balmer series because J. J. Balmer was able to formulate a simple mathematical relation among the frequencies (in It S). The ultraviolet series shown in Figure 15-3 was... 

Weight-weight calculations, 226 Werner, Alfred, 393 Wintergreen, oil of, 340 Wollaston, W. H., 258 Wondering Why, 5, 8,16, 155 Woodward, Robert Burns, 435 Work, 114... 

Rhodium was discovered in 1803 by the eminent Norfolk scientist W.H. Wollaston he dissolved platinum metal concentrates in aqua regia and found that on removing platinum and palladium he was left with a red solution. From this he obtained the salt Na3RhCl6, which yielded the metal on reduction with hydrogen. The rose-red colour (Greek rhodon) of many rhodium salts gave the element its name. 

Palladium and platinum are the longest known and most studied of the six platinum metals [1-11], a reflection of their abundance and consequent availability. Platinum occurs naturally as the element, generally with small amounts of the other platinum metals. It was used as a silver substitute by Colombian Indians and first observed there by Ulloa (1736), who called it platina del Pinto ( little silver of the Pinto river ) but the first sample was actually brought to Europe in 1741 by Charles Wood, Assay Master of Jamaica. Palladium was isolated in 1803 by W.H. Wollaston, who was studying the aqua regia-soluble portion of platinum ores (he announced his discovery by an anonymous leaflet advertising its sale through a shop in Soho) and named it after the newly discovered asteroid Pallas [12],... 

Fig. 5.19 Electrodes used in voltammetry. A—dropping mercury electrode (DME). R denotes the reservoir filled with mercury and connected by a plastic tube to the glass capillary at the tip of which the mercury drop is formed. B—ultramicroelectrode (UME). The actual electrode is the microdisk at the tip of a Wollaston wire (a material often used for UME) sealed in the glass tube...

William Hyde Wollaston (1766-1828) found rhodium in crude platinum. 

Noise correlation function, 22 113 Noise equivalent power (NEP), 19 133 Noise spectral density, 19 134-135 Nomarski, Georges, 16 480 Nomarski-modified Wollaston prism, 16 481... 

William Wollaston wrote, "The atomic theory could not rest content with a knowledge of the relative weights of elementary atoms but would have to be completed by a geometrical conception of the arrangement of the elementary particles in all the three dimensions of solid extension." In "On Superacid and Sub-acid... 

Rhodium (Rh, [Kr]4t/x5v1), name from the Greek po ov (rhodon rose). Discovered (1803) by the English chemist William Hyde Wollaston. 

Rhodium - the atomic number is 45 and the chemical symbol is Rh. The name derives from the Greek rhodon for rose because of the rose color of dilute solutions of its salts . It was discovered by the English chemist and physicist William Hyde Wollaston in 1803 in a crude platinum ore. 

The story became more complicated when in 1809 the Enghsh scientist William Hyde Wollaston (1766—1828) analyzed the sample mineral and declared that columbium was really the same element as tantalum ( Ta). This error is understandable given that the level of analytical equipment available to scientists in those days was fairly primitive. Also, tantalum and niobium are very similar metals that are usually found together and thus are difficult to separate for analysis. 

William Hyde Wollaston (1766—1828), who had also discovered palladium (4gPd) in the early 1800s, announced in 1803 his discovery of another metal that he had isolated... 

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