COINAGE METALS Dr Althea Rodriguez Arenajo COINAGE METALS

COINAGE METALS Dr. Althea Rodriguez Arenajo

COINAGE METALS �Copper, Silver and Gold are the members of this family �The group was named because they have been employed for ornamental and coinage purposes �They are closely related with nickel, palladium and platinum �The following are the properties of the metals:

COINAGE METALS 1. Occur free in nature and are easily recovered from their compounds 2. Are low in the electromotive series, not very active chemically, displaced by most metals 3. Oxides and hydroxides are feebly basic (except Ag 2 O) 4. The halides are nearly insoluble in water (except Ag)

COINAGE METALS 5. Copper and Gold have 2 series, Silver has 1 6. All of them form complex ions 7. Copper is slowly oxidized in air, but rapidly when finely divided and heated in oxygen

COPPER � Copper was probably the first metal used by man in fashioning various domestic implements and weapons � Cuprite(Cu 2 O), a red copper ore occurs abundantly and the most impt ore � The feathers of certain birds contain pigments made of copper � Copper is malleable and ductile having a red color by reflected light and greenish color by transmitted light

COPPER �Copper is an excellent conductor of heat (surpassed only by silver and gold) and electricity (surpassed only by gold) �The two copper oxides are red cuprous and black cupric �All copper compounds are insoluble in water �Produce a blue ppt with NH 3 water

COPPER �Cupric salts added with K 4 Fe(CN)6 gives reddish brown ppt �Cupric ions with H 2 S turns black Pharmacologic Action of copper ion: �Copper and iron metabolism are interrelated, it has importance in homopoies

COPPER �Hepatolenticular degeneration (Wilson’s disease) results from inability to regulate copper balance �The consequence is that toxic amounts of copper are deposited in various tissues (liver, lungs) �The disease may be treated with chelating agents such as Dimercaprol and edelates

COPPER �Internally, copper is a potential aid to iron assimilation and as emesis �After absorption, Cu is found as copper nucleinate in the liver, blood and bile �Externally, Cu acts as astringent when applied to mucous membrane and abraded surfaces �An effective fungicide (1: 1, 000)

COPPER �Has value in water treatment to remove algae and also of fungus that afflicts humans �A copper compound in tetralin (Cuprex) is used in pediculosis of the head, body or clothing �Copper is not an effective bactericide, only mild antiseptic �Its action is only bacteriostatic

COPPER Important Compounds: 1. Cupric Sulfate NF- Bluestone, Blue Vitriol � Stimulates the vomiting reflex before there is time for any local irritant action � It is not absorbed, except by corroded stomach therefore, do not produce systemic effects

COPPER �Bordeaux Mixture( copper in combination with lime) is used as fungicide �Used to purify drinking water and swimming pools �In combination with iron or vitamins, has hematinic property �Used externally for its fungicidal action in 1 -5 sol’n

SILVER �Ag is used in making articles of value like coins, ornaments, jewelry �The name Silver was derived from Greek which means “shining” �The Alchemist named it “Luna”, characetrized by crescent moon �The name Luna has survived in Lunar caustic, silver nitrate �Pure silver is a white metal having a metallic luster

SILVER � The most ductile and malleable of all metals, except gold � The best conductor of electricity � Silver cyanide complex is added to silver sol’n for electroplating � Silver salts gives a white curdy ppt of Ag. Cl when treated with HCl � Ammoniacal sol’n of silver salts with formaldehyde and warmed, formed ‘silver mirror’ on the walls of container

SILVER Important Compouds: 1. Silver Nitrate (Argentii Nitras) � It is used routinely in the form of 1% sol’n for instillation in the eyes of newborn babies for gonorrheal infection which is still a legal requirement in some states (against Ophthalmia neotorium) Dose: 1 drop in each eye

SILVER �Silver Nitrate pencil (Toughened Silver Nitrate) – used for removing warts and other skin excresences and for canker sore in the mouth �A dose of 0. 5% is used to treat �severe 1 st degree burns with 80% recovery 2. Mild Silver Protein ( Mild Protargin) �It is used as local antibacterial in aqueous sol’n at conc from 5 -25%

SILVER �It is used as mild antiseptic in the eye, ear, nose and throat 3. Colloidl Silver Chloride (Lunosol) Use: prophylaxis against and treatment of infections of the accessible mucous membrane such as genitourinary tract and the eye 4. Silver Picrate (Picragol, Picrotol, Silver trinitrophenlate)

SILVER Use: in the treatment of vaginitis resulting from Trichomonas vaginales and Monilia albicans 5. Strong Silver Protein (Protargol, Argentum Proteinicum Forte, Strong Protargin ) �A potent germicide used in conc of 0. 25 to 0. 5% for irrigation of the bladder and urethra

GOLD �Recognized as the King of all metals since the earliest times because of its color, scarcity and permanency in contact with the atmosphere �Valued from the earliest ages for making jewelry, coin and etc. �The symbol Au was taken from the Greek aurum, a universal symbol of highest purity and value

GOLD �Gold is one of the most inactive and permanent of all metals �Aqua Regia, best reagent for dissolving gold, can also be dissolve by chlorine and bromine water �Reacts with Na. OH and gives a brown ppt of auric hydroxide �Forms soluble salts with acid/base, has amphoteric property

GOLD Other amphoteric substances are: aluminum, tin, zinc, and lead �Gold when treatd with stannous chloride sol’n slowly forms purple ppt known as purple of Cassius �Modern gold therapy started with the discovery by Koch in 1890, that gold cyanide was effective in vitro against tubercle bacillus.

GOLD 1. Gold Sodium Thiosulfate NF Use: treatment of nondisseminated lupus erythromatosus, and rheumatoid arhritis Dose: 5 – 25 mg, intramuscularly 2. Aurothioglycanilide 3. Aurothioglucose 4. Au Na Thiomalate – (Myochrysine) antirheumatic, rheumatoid arthritis