PF1009 2024 3 Inorganic Compounds PDF

Pharmaceutical Chemistry Inorganic Compounds Dr. J.J. Keating 1  Compound Substance consisting of atoms of two or more elements in a definite ratio. Empirical formula Shows the relative numbers of atoms of eac...

Pharmaceutical Chemistry Inorganic Compounds Dr. J.J. Keating 1  Compound Substance consisting of atoms of two or more elements in a definite ratio. Empirical formula Shows the relative numbers of atoms of each element in a compound in terms of the chemical symbols of the elements as their lowest common multiple (LCM). A laboratory analysis of Vitamin C (ascorbic acid) showed that its mass percentage composition is 40.9% C, 4.57% H, 54.5% O. What is the empirical formula of ascorbic acid? Molecular formula Actual number of atoms of each element present in a molecule. For Vitamin C: empirical formula = C3H4O3 molecular formula = C6H8O6 C6H8O6 Vitamin C (ascorbic acid) 2  Would you Ban Dihydrogen Monoxide? Nathan Zohner, a student at Eagle Rock Junior High School in Idaho, United States, conducted a clever science-fair experiment that tested anti-technology sentiments and associated chemical phobias in 1997. He invited people to sign a petition that demanded either strict control of, or a total ban on, dihydrogen monoxide. He listed some of the odious properties of this colourless and odourless substance: 1. It is a major component of acid rain. 2. It eventually dissolves nearly anything it comes into contact with. 3. It is lethal if accidentally inhaled. 4. It can cause severe burns in its gaseous state. 5. It has been found in tumours of terminal cancer patients. 43/50 people approached by Zohner signed the petition, 6 were undecided, and 1 was a strong supporter of dihydrogen monoxide and refused to sign. 86% of the passers-by voted to ban water (H2O) from the environment ! We live in a world made of chemicals. Table salt is sodium chloride; table sugar is a disaccharide; a major ingredient of vinegar is acetic acid; glass is a super-cooled liquid silicate; our stomach contains 1 M hydrochloric acid. It is important to be able to recognise a chemical by its name. 3  Inorganic Chemical Nomenclature – Cations Common name gives little or no clue to the compounds composition. Systematic name reveals which elements are present and is constructed by certain rules. Naming cations Metallic elements – add the word “ion” to the name of the element. Na+ = sodium ion Some elements always form cations of one characteristic charge number. Element Characteristic charge number Group I +1 Group II +2 Zn, Cd +2 Al +3 4  Inorganic Chemical Nomenclature – Cations To distinguish between two ions of the same element, use the Stock number. Cu+ = copper(I) ion Cu2+ = copper(II) ion Older nomenclature – “ous” and “ic” were used and/or Latin names of compounds. Element Cation Old name New name Element Cation Old name New name Cobalt Co2+ cobaltous cobalt(I) Mercury Hg22+ mercurous mercury(I) Co3+ cobaltic cobalt(I) Hg2+ mercuric mercury(II) Copper Cu+ cuprous copper(I) Tin Sn2+ stannous tin(II) Cu2+ cupric copper(II) Sn4+ stannic tin(IV) Iron Fe2+ ferrous iron(II) Fe3+ ferric iron(III) Lead Pb2+ plumbous lead(II) Pb3+ plumbic lead(III) Copper (cuprum); Iron (ferrum); Lead (plumbum); FeSO4 Mercury (hydragyrum); Tin (stannum) ferrous sulfate 5  Ions and Ionic Compounds – Cations Cation: +ve charged ion – loss of e– from a neutral atom. Anion: –ve charged ion – gain of e– from a neutral atom. Cations Group I, II, III – group number = max. +ve charge of the atoms. Group IV and transition metals – variable charges. Li2CO3 lithium carbonate Group I Group II Transition metals Group III Group IV Li+ Be2+ Na+ Mg2+ Al3+ K+ Ca2+ Fe2+, Fe3+, Cu+, Cu2+, Zn2+ Ga3+ Rb+ Sr2+ Ag+, Cd2+ In+, In3+ Sn2+, Sn4+ Cs+ Ba2+ Au+, Au3+ Tl+, Tl3+ Pb2+, Pb4+ 6  Ions and Ionic Compounds – Anions Anions Ability to gain e–. Characteristic of atoms of the nonmetallic elements. Maximum charge = number of monoatomic anion elements = group number – 8. When naming monoatomic anions, add “-ide” to the stem of the element. Group V Group VI Group VII Nitride N3– Oxide O2– Fluoride F– Phosphide P3– Sulfide S2– Chloride Cl– Cyanide CN– Hydroxide OH– Bromide Br– Iodide I– NaF sodium fluoride 7  Ions and Ionic Compounds – Oxanions Oxanions Names formed by adding “-ate” to the stem of the name of the element that is not oxygen. The term “-ite” is sometimes used to indicate an element stem of an anion which has one less oxygen than its “-ate” homologue. Name Ion Name Ion Phosphate PO43– Nitrate NO 3 – Hydrogenphosphate HPO42– Nitrite NO 2 – Dihydrogenphosphate H2PO4– Sulfate SO 4 2– Carbonate CO32– Hydrogensulfate/ HSO 4 – Bisulfate Hydrogencarbonate/ HCO3– Bicarbonate Sulfite SO32– Chlorate ClO3 – Hydroxide OH – Chlorite ClO2 – NaHCO3 (4.2% w/v) Ammonium NH 4 + sodium bicarbonate 8  Acid Nomenclature Hydrogen halides HCl = hydrogen chloride, aq. HCl = hydrochloric acid HBr = hydrogen bromide, aq. HBr = hydrobromic acid Oxoacids Replace “-ate” by “-ic acid” Replace “-ite” by “-ous acid” H2CO3 = carbonic acid H2SO3 = sulfurous acid NaOCl 4.5% w/w sodium hypochlorite Oxanions Some oxanions have relatives with a smaller or larger proportion of oxygen: Perchlorate ClO4 – HClO4 perchloric acid Chlorate ClO3 – HClO3 chloric acid Chlorite ClO2 – HClO2 chlorous acid Hypochlorite ClO – HClO hypochlorous acid Chloride Cl – HCl hydrochloric acid 9  Naming Ionic Compounds Name built in the order (cation)(anion), with the word “ion” omitted. CuCl = copper(I) chloride CuCl2 = copper(II) chloride Prefixes are not used in the systematic nomenclature of ionic compounds as the numbers of anions present can be determined from the charge of the cation: CuCl2 = copper(II) chloride, not copper(II) dichloride CaCl2 = calcium chloride, Al2O3 = aluminium oxide MnO2 = manganese(IV) oxide = manganese dioxide TiO2 = titanium(IV) oxide = titanium dioxide (excipient) TiO2 titanium dioxide 10 Multi-Vitamin Preparations CaHPO4 CaCO3 MgO O Fe2+ C4H2FeO4   O O O ZnO MnSO4 CuSO4 CrCl3 Na2MoO4 KI Na2SeO4 11  Infant Formula O Ca3(PO4)2 K+  O O HO K+ K3C6H5O7   O O K + O NaCl MgCl2 KCl FeSO4 ZnSO4 CuSO4 KI KOH Na2SeO4 12