Silver authenticity

The precipitates were collected in sintered glass crucibles, washed with alcohol, and dried in vacuum. The weight of silver chloride was 0.3488 g. Authentic samples of TBTC1 (M T Chemicals), when gravimetrically analyzed under identical conditions, gave an assay of 95%. Thus the conversion from TBTA to TBTC1 is 94% in sample 4-4. 

Molar ratio of glycosyl chloride and silver(I) tetrafluoroborate was 1 1.2, unless otherwise stated. b Compounds obtained were proved to be identical with authentic samples. 

The data represented by the open squares in Figure 5 were obtained from streaks of modern fake Sasanian coins (4). Note that the gold levels for these fake coins are usually appreciably less than those for authentic coins. This is because silver used in the last 100 years almost always... 

Commercial persistence of authenticity Why are promotional efforts richly imbued with promises of real, authentic experiences and opportunities Social differentiation and status markers for tourists and promoters maintain the commercial use of the term (Silver, 1993). 

Silver, A. (1993) Marketing authenticity in Third World countries. Annals of Tourism Research 20 (2) 302-318. 

Because of the chemical similarities between silver and copper, silver acetylides were implicated in a catalytic cycle comparable to that proposed for the copper-catalyzed reaction, and the group has produced undeniable evidence for their participation. Authentic samples of silver acetylides were found to couple with enol Inflates under the same conditions as for the catalytic reaction to produce enynes in... 

Further study is indicated, especially under experimental conditions that allow the detection of cadmium in the presence of high concentrations of silver. The controversy surrounding the possibility of the use of cadmium compounds by goldsmiths of antiquity could more easily be elucidated if other analytical research teams were involved in analyses of jewelry of unquestionable authenticity from the same period and origin as those reported here. A more extensive study of ancient textbooks by both linguists and scientists would probably shed additional light on the subject. 

The incorrect description by Orbeli and Trever of Sasanian silver-smithing techniques did not misinform the serious scholar alone the modem forger was fooled also. Many Sasanian silver objects exist that were manufactured either by the double shell technique or by casting. Since our study indicated that these techniques were not used by the Sasanian silversmith, the authenticity of such objects should be considered very questionable. (Combined anomalies in style, iconography, elemental analysis, method of manufacture, and corrosion should provide, of course, the definitive evidence that these objects are not made by a Sasanian silversmith.)... 

An authentic silver gilt plate is shown in Figure 7 its x-ray radiograph (Figure 8) is consistent with a plate shaped by hammering and... 

The more commonly employed procedure (method A), applied to the reaction of ( )-l,2-diphenylethylene with ethyl chlorocarbamate in the presence of silver nitrate, is described in the Organic Syntheses series79. The syn diastereoselectivity was proved only in the case of cyclohexene, by comparison of the cis product with an authentic sample of the trans-isomer. 

C, and the excess Xe and AHF were removed under vacuum, After the mixture was warmed 10 - 20 C, colorless crystals were observed on the walls of the tube, in addition to the dark brown solid in ihe bottom of ii. This colorless material was transferred under vacuum to a trap, Raman spectroscopy showed a strong band al 496 cm, characteristic of XeFj, The dark-brown silver fluoride remaining in the tube gave an X-ray powder photograph identical with that of authentic samples of face-centered orthorhombic AgFj. These observations are in accord with the reaction expressed in eq 6,... 

Triphenylmethyl-4-methyl-2,8,9-trioxa-1-phosphaadamantane Tetrafluoroborate from Isomers A and B. To 1.00 g. (5.12 mmoles) of silver tetrafiuoroborate in acetone (10 ml.) was added a solution of 1.43 g. (5.12 mmoles) of triphenylmethyl chloride in acetone (15 ml.). After 5 min., the filtered solution was added to a stirred suspension of 0.90 g. (12 mmoles) of isomer A in acetone (20 ml.). After 4 hrs., a colorless precipitate formed which was filtered off and dried under vacuum at room temperature. The colorless solid (0.52 g., 30% yield), was shown to be identical with an authentic sample of l-triphenylmethyl-4-methyl-2,8,9-trioxa-l-phosphaadamantane tetrafluoroborate (16) by infrared spectroscopy. A similar procedure with isomer B gave the same product in 31% yield. 

Although modern counterfeiters have mastered the duplication of the outside appearance of precious metals, some simple chemical/physical testing can determine their authenticity. Consult a reference book and determine the densities of gold, silver, copper, lead, iron, nickel, and zinc. 

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