PCQA111 Week 10 Group IIIA and IIIB PDF

 UNIT OUTCOMES At the end of this unit, the students are expected to: Demonstrate a comprehensive understanding of the chemistry of metals, non-metals and metalloids.  UNIT OUTLINE ✔ Elements ✔ Properties ✔ Identification Tests ✔ Compounds and Their Uses  CH...

 UNIT OUTCOMES At the end of this unit, the students are expected to: Demonstrate a comprehensive understanding of the chemistry of metals, non-metals and metalloids.  UNIT OUTLINE ✔ Elements ✔ Properties ✔ Identification Tests ✔ Compounds and Their Uses  CHECKLIST Read the available learning references before the discussion. Search for the meaning of the following terminologies. Listen and participate in the board discussion.  GROUP III-A ELEMENTS THE BORON FAMILY Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), and Thallium (Tl) *The first two are the most important to pharmacy.  Only one of these elements, aluminum can be considered to be abundant. In fact, it is the most common metal and the third most common element in the earth’s crust. *Only oxygen and silicon are more abundant.  CHEMICAL PROPERTIES Boron bonding tends to be more covalent than ionic; it is also referred to as a metalloid. Aluminum may form both covalent and ionic bonds.  CHEMICAL PROPERTIES The metals of this group readily oxidizes when heated in air, although they are stable at ordinary temperatures. The oxides are readily reduced back to the free metal.  CHEMICAL PROPERTIES The metals react readily with sulfur and the halogens. The hydroxides tend to show amphoteric properties with the exceptions of the top and bottom elements of the group.  CHEMICAL EQUATIONS 4M + 3 O2  2 M 2O3 (M – Al, B) 2M + 3 X2  2 MX3 (M – Al, B)  CHEMICAL EQUATIONS Al(OH)3 + 3 HCl  AlCl3 + 3 H2O Al(OH)3 + NaOH  NaAlO2 + 2 H2O IDENTIFICATION TEST Aluminum NH3: white gelatinous ppt. of Al(OH)3 *Al(OH)3 adsorbs the color of the dye, aluminon producing a red lake. Thenard’s Blue Test Co(NO3)2 + NH3  Co(AlO2)2 Blue ash -- cobalt meta-aluminate COMPOUNDS Boron Non-metal Component of glass SOURCES: Tincal – Na3BO3 H3BO3 Boron Hardness of Crystalline Boron – Valuable substitute for diamond in glass cutting and gem polishing  Borates Reacts with turmeric paper Use in vulcanizing rubber  Boric acid H3BO3 “Boracic acid”, “Sal sedativum”, “Sal sativum” Toxic by ingestion Absorbed in broken skin Buffer in ophthalmic preparation Tonicity adjusting agent E-VALUE=0.52 Antiseptic Eyewash: 2.45% - 2.5% Boroglycerin glycerite – suppository base  Boromycin Isolated from Streptomyces antibioticus. Used as anti-HIV in-vitro  Sodium borate Na2B4O7 “Borax” Sodium tetraborate Dobell’s Solution – astringent or antiseptic wash for throat and nose Eye wash Component of cold cream and in the preparation of sodium borate preparation.  Buffers (1)Phosphate Buffer System (2)Borate Buffer System  Phosphate Buffer System Has the advantage of containing the dihydrogen and monohydrogen phosphate ions, one of the physiological buffer pairs normally found in the body – Ex: Sorensen phosphate buffer system  Phosphate Buffer System Disadvantage: – insolubility of the phosphate salts of such metals such as Ag, Zn and Al – it supports microbial growth  Borate Buffer System Borate buffer system has been used in preparations containing metals that would otherwise precipitate in the presence of phosphate. Since BORATES ARE TOXIC, these buffer system are suitable in external preparations, ophthalmic and nasal solutions but are contraindicated in parenteral solutions  3 primary borate buffer system 1) Feldman’s Buffer System (pH 7-8.2) – consists of solution containing boric acid, sodium chloride (to make it isotonic) and the alkaline solution containing sodium borate  3 primary borate buffer system 2) Atkins and Pantin Buffer System (pH 7.6-11) – consists of alkaline solution of sodium carbonate and acid buffer solution of boric acid and sodium chloride.  3 primary borate buffer system 3) Gifford Buffer System (pH 6-7.8) – similar to Feldman’s Buffer System however in place of NaCl, potassium chloride is used to make it hypotonic. Aluminum SOURCES: Cryolite – (Na3AlF6, sodium hexafluoroaluminate) Chief Source: Bauxite ore Aluminum Pharmaceutical Uses of Aluminum: Deodorant Protectant Antiseptic Antiperspirant Aluminum Adverse Effects:  Constipation Toxicity: Shaver’s disease/ Bauxite pneumoconiosis – A progressive lung disorder caused by exposure to aluminum oxide which is present in bauxite fumes  Aluminum chloride astringent, antiseptic, component of deodorant Aluminum hydroxide Al(OH)3 Amphojel Cremalin gel Adverse Events: Constipation PO4 deficiency  Aluminum phosphate (AlPO4) “Phosphagel” Antacid Astringent Aluminum carbonate Al2(CO3)3 Treatment of phosphatic calculi  Alum Al K(SO4)2.12H2O Deodorant Aluminum oxide (Al2O3) Alumina Treatment of silicosis  Aluminum acetate Al(CH3COO-)3 Burrow’s solution, Domeboro’s soln Astringent Dihydroxyaluminum amino acetate – Gastric antacid – Magma and tablet  Aluminum silicates KAOLIN -”native hydrated aluminum silicate”, “china clay” -adsorbent & demulcent in diarrhea BENTONITE (Wilkinite) -“native hydrated colloidal Al silicates -mineral soap, soap clay - suspending agent PUMICE -”Na, K, Al silicates”, Piedra Pomez -volcanic origin -dental abrasive, dentrifice -grades of pumice: flour/superfine, fine, coarse Gallium Aka: Eka-aluminum Substitute for Hg in manufacture of arc lamps. Treatment of cancer related hypercalcemia Thallium “Thallos” Green shoot or green twig 2nd most toxic metal GROUP III-B ELEMENTS The Lanthanide Series The Actinide Series  GROUP III-B THE SCANDIUM SUBGROUP This is a very long group of elements, which include scandium, yttrium, lanthanum, actinium and the two inner transition series.  Scandium AKA: Eka-boron Discovered by Lars Fredrik Nilson, 1879. Occurs in euxenite and gadolinite. A silvery metal which develops a yellow top cast on exposure to air. Used in light weight alloys in aircraft.  Yttrium Occurs in Yttria. It is present in elevated levels in the moon rock returned by Apollo. Silvery metal and stable in air. Used in the red phosphors in colored- TV tubes and magnets in microwave equipment and lasers.  What are the two inner transition series? Lanthanides (rare elements, atomic number 58-71) and Actinides (atomic number 89-103).  All lanthanides are f-block elements, corresponding to the filling of the 4f electron shell, except for lutetium which is a d-block lanthanide. The lanthanide series is named after lanthanum.  Lanthanide series Lanthanum Terbium Cerium Dysprosium Praseodymium Holmium Neodymium Erbium Promethium Thulium Samarium Ytterbium Europium Gadolinium Lutetium  Lanthanide series All the lanthanide elements (La through Lu) occur in mixtures, which are hard to separate due to similarity in chemical properties.  Actinide series All the actinide elements (Ac through Lr) beyond uranium are prepared synthetically and only exist as radioactive isotopes, which are usually not very stable.  Actinide series The actinide series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 90 – 103. The actinide series is named after actinium.  The actinide series is included in some definitions of the rare earth elements. IUPAC is currently recommending the name actinoid rather than actinide, as the suffix "-ide" generally indicates ions.  Actinide series Actinium Berkelium Thorium Californium Protactinium Einsteinium Uranium Fermium Neptunium mendelevium Plutonium Nobelium Americium Lawrencium Curium  Actinide series All these elements form compounds with the 3+ oxidation state and also the 2+ state is known.  Actinide series The elements have physical properties that are typical metals. They are all quite reactive chemically and the oxides are basic.  REFERENCES Qualitative Analysis by Esmarch S. Gilreath Remington: The Science and Practice of Pharmacy 21st Edition ANY QUESTIONS? 55