Transcript chemrat.com
Intro to Inorganic Chemical Nomenclature Part 1, Binary Compounds This lesson was divided into two parts Part 1 Binary Compounds • In this first video we are studying the nomenclature of Binary Compounds • There is also a second video dealing with the nomenclature of Polyatomic Compounds. • Youtube ‘Inorganic Chemical Nomenclature Part 2 Polyatomic Compounds’ 1 Intro to Inorganic Chemical Nomenclature Part 1 Binary Compounds Chemical Nomenclature = writing the formulas and names of chemicals. Using three systems of inorganic nomenclature … • the Stock system • the Prefix system • the Ous-Ic system This requires that you learn the names, formulas and oxidation numbers (Ox #’s) of a variety of monatomic elements and polyatomic ions needed for binary and polyatomic compounds. This lesson is designed for a 1st semester college chemistry student and assumes that the student already has a working knowledge of electron configuration, electronegativity, chemical bonding, and acid ionization. 2 Intro to Inorganic Chemical Nomenclature Chemical Formulas of Binary Compounds: Binary compounds are made of two different kinds of atoms. A chemical formula tells us which atoms and how many atoms of each kind are present in a chemical compound. Look at the structure of a water molecule. Each water molecule contains 2 hydrogen atoms and 1 oxygen atom. symbol for oxygen symbol for hydrogen subscript indicates 2 hydrogen atoms H2O implied subscript of 1 indicating 1 oxygen atom A subscript of ‘1’ is never written in formulas. Look at the formulas on the right and identify the error in each. H2O/1 H2O /(H)/2O OH2 3 1A 1H (2.1) Electronegativity (EN) values of A-group Elements EN: hydrogen 1 -1 3Li (1.0) lithium 1 --11Na (1.0) sodium 1 --19K (0.9) 2A 4Be(1.5) beryllium 2 --12Mg (1.2) magnesium 1 --37Rb (0.9) 2 --20Ca (1.0) calcium 2 --38Sr (1.0) rubidium strontium 1 --55Cs (0.8) cesium 1 --87Fr (0.8) 2 --56Ba (1.0) barium 2 --88Ra (1.0) radium 2 --- potassium francium 1 --- 3A 5B (2.0) 4A 6C 5A (2.5) 7N (3.0) boron carbon nitrogen 3 2, 4 2,3,4,5 ---4 -3 14Si (1.8) 13Al (1.5) 15P (2.1) aluminum silicon phosphorus +3 3, 4, 5 4 ---3 --31Ga (1.7) 33As (2.1) 32Ge (1.9) gallium germanium arsenic 4 3 3, 5 -----3 50Sn (1.8) 49In (1.6) 51Sb (1.9) indium antimony tin 1, 3 3, 5 2, 4 ---3 --82Pb (1.7) 83Bi (1.8) 81Tl (1.6) thallium lead bismuth 1, 3 2, 4 3, 5 ------- 6A 8O (3.5) oxygen ---2 16S (2.5) sulfur 2, 4, 6 -2 34Se (2.4) selenium 4, 6 -2 52Te (2.1) tellurium 4, 6 -2 84Po (1.9) polonium 2, 4 --- 7A 9F (4.0) fluorine ---1 17Cl (3.0) chlorine 1,3,5,7 -1 35Br (2.8) bromine 1, 5 -1 53I (2.5) iodine 1, 5, 7 -1 85At (2.1) astatine H2O 2.1 (H) < 3.5 (O) The less EN atom is listed first. Practice: Write the formula of a compound made of … • one S & two Na atoms Na2S 1.0 (Na) < 2.5 (S) • one P & three Br atoms PBr3 2.1 (P) < 2.8 (Br) • two Cl’s & one Mg atom MgCl2 1.2 (Mg) < 3.0 (Cl) In formulas of ionic compounds, symbols of metals precede nonmetals because all metals have lower EN values than any nonmetal. 4 Chemical Formulas of Binary Compounds Use the table of EN values to write the chemical formulas of the compounds shown below… EN: Al (1.5) < O (3.5) Al2O3 C (2.5) < O (3.5) CO2 Ca (1.0) < F (4.0) CaF2 5 Some Exceptions in Chemical Formulas of Binary Compounds The least Electronegative atom in binary compounds are usually listed first, but there are a few historical exceptions … • In the formulas of hydrocarbon compounds (abbreviated HC’s), which are compounds containing only hydrogen and carbon, C (EN=2.5) is listed before H (EN=2.1), even though C has the higher EN value. CH4, methane, is the major component of natural gas. C2H6, ethane is the 2nd largest component of natural gas • Most formulas of binary compounds, in which H is listed first, are acids, such as hydrochloric acid, HCl and hydrofluoric acid, HF. • HC’s are not acidic so their H’s are listed last. 6 More Exceptions in Chemical Formulas of Binary Compounds • In the formulas of binary compounds containing nitrogen, N is usually listed first regardless of its EN value. In N2O5, N (3.0) < O (3.5) N is less EN and written first. In ammonia, NH3, EN N (3.0) > H (2.1), but N is written first. • Ammonia, NH3, is not acidic. It’s a moderately strong base. • Listing H first would make ammonia look acidic … H3N / 7 Naming Binary Compounds There are three systems for naming binary compounds 1. The Stock System (the most comprehensive) e.g., sodium chloride 2. The Prefix System (for nonmetal compounds only) e.g., carbon monoxide, carbon dioxide 3. The ous-ic system (has limited use) e.g., ferrous oxide, ferric oxide 8 The Stock System for Naming Binary Compounds CaCl2 = calcium chloride name of less name of more EN EN atom first atom ends in ‘ide’ a space between chlorine chloride • • • Al2O3 = aluminum oxide name of less name of more EN EN atom first atom ends in ‘ide’ a space between oxygen oxide In ionic compounds (made of metal cations, ⊕ and nonmetal anions, ⊖), the less EN atom is a metal cation, and the more EN atom is a nonmetal anion. The name of the metal cation is the same as the element’s name but the anion’s name ends in ‘ide’. Note that the Stock system name does not tell us the relative number of atoms in the formula. This will be explained later. 9 Learn the anion names & charges. 1A 1H (2.1) 8A He hydrogen 1 -1 3Li (1.0) lithium 1 --11Na (1.0) sodium 1 --19K (0.9) 2A 4Be(1.5) beryllium 2 --12Mg (1.2) magnesium 1 --37Rb (0.9) 2 --20Ca (1.0) calcium 2 --38Sr (1.0) rubidium strontium 1 --- 2 --- potassium 3A 5B (2.0) 4A 6C 5A (2.5) 7N (3.0) boron carbon nitrogen 3 2, 4 2,3,4,5 ---4 -3 14Si (1.8) 13Al (1.5) 15P (2.1) aluminum silicon phosphorus +3 3, 4, 5 4 ---3 --31Ga (1.7) 33As (2.1) 32Ge (1.9) gallium germanium arsenic 4 3 3, 5 -----3 50Sn (1.8) 49In (1.6) 51Sb (1.9) indium antimony tin 1, 3 3, 5 2, 4 ---3 --- 6A 8O (3.5) oxygen ---2 16S (2.5) sulfur 2, 4, 6 -2 34Se (2.4) selenium 4, 6 -2 52Te (2.1) tellurium 4, 6 -2 7A 9F (4.0) fluorine ---1 17Cl (3.0) chlorine 1,3,5,7 -1 35Br (2.8) bromine 1, 5 -1 53I (2.5) iodine 1, 5, 7 -1 Nonmetal anions gain enough electrons to fill their valence shell to become isoelectronic with the nearest noble gas. Helium Ne Neon Ar Argon Anions typically have only 1 possible Ox #, which is easy to learn if you know their Group number on the PD table Kr Krypton Xe Xenon 10 Practice naming these binary compounds using the Stock system: K3P potassium phosphide BaBr2 barium bromide MgO magnesium oxide CaH2 calcium hydride Al2S3 aluminum sulfide Na2Se sodium selenide Ca3N2 calcium nitride SrCl2 strontium chloride MgF2 magnesium fluoride B2O3 boron oxide LiI lithium iodide SiC silicon carbide Be2C beryllium carbide HF hydrogen fluoride Note that the last three examples are not ionic compounds. They are composed of metalloids and/or nonmetals only, yet the Stock system names all compounds as if they were ionic. The less EN atom is first (using the atom’s name). The more EN atom is last (using the anion’s ‘ide’ name). 11 Writing Chemical Formulas of Binary Compounds In order to write formulas and name compounds, you will need the ‘oxidation numbers’ (Ox #’s) of the atoms/ions in a compound. Ox #’s are explained in detail in a video entitled ‘Oxidation Numbers’ and will only be discussed briefly in this lesson. What is an oxidation number (Ox #)? Ox # is a charge assigned to an atom or ion in a compound. All pure elements have an Ox # = 0, e.g., Ox # Cu=0, H2=0, S8=0. About 20 elements have only one Ox # (fixed Ox #’s), other than 0, and they must be memorized, but it is easy to do so if you learn their position on the periodic table. The Ox #’s of other atoms/ions are calculated from the chemical formula. 12 Fixed Ox #’s are highlighted (red and yellow). Metals cannot have ⊖ Ox #’s (they never gain e’s). Most nonmetals can have ⊖ or ⊕ Ox #’s, e.g., Cl in ICl (Cl = -1), Cl in ClF (Cl = +1), Cl in ClO2 (Cl = +4), Cl in ClF7 (Cl = +7). Note that the nonmetal with higher EN always gets a ⊖ Ox # 1H (2.1) symbol & proton number hydrogen Key 1 -1 Li (1.0) electronegativity (EN) 2A Be(1.5) 3 4 lithium beryllium 1 --- 2 --- 11 Fixed Ox #’s are easily memorized by knowing their A-Group number on the PD table. Other Ox #’s can all be calculated. 7 N (3.0) 3A -3 6 7 boron carbon negative oxidation numbers 3 --- 2, 4 -4 nitrogen oxygen 2,3,4,5 --- Al (1.5) 13 sodium magnesium aluminum 1 --- 2 --- 3 --- 3B 4B 5B 6B 7B 6A B (2.0) Na (1.0) 12Mg (1.2) 8B 8B 8B 1B 2B C (2.5) 5A positive oxidation numbers 5 nitrogen 2,3,4,5 4A Si (1.8) 14 N (3.0) O (3.5) 8 -3 P (2.1) 15 7A F (4.0) 9 fluorine ---1 -2 S (2.5) 16 Cl (3.0) 17 silicon phosphorus 4 --- sulfur 2, 4, 6 chlorine 3, 4, 5 -3 -2 -1 1,3,5,7 Cr (1.6) 25Mn (1.6) 26Fe (1.7) 27Co (1.7) 28Ni (1.8) 29Cu (1.8) 30Zn (1.6) 31Ga (1.7) 32Ge (1.9) 33As (2.1) 34Se (2.4) 35Br (2.8) potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine 2,3,4,6,7 4 2,3,4,5 2, 3, 6 1 3 3, 4 4, 6 3, 5 2 3 1, 5 2, 3 2, 3 1, 2 2, 3 2 ---------3 -2 -------1 --------------19 K (0.9) Ca (1.0) 20 Sc (1.3) 21 Ti (1.4) 22 23 V (1.5) 24 Zr (1.3) 41Nb (1.5) 42Mo (1.6) 43Tc (1.7) 44Ru (1.8) 45Rh (1.8) 46Pd (1.8) 47Ag (1.9) 48Cd (1.6) 49In (1.6) rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium 2,3,4 2, 4 --1 2 3 4 3,5 2 1, 3 2, 3, 4 2,3,4,5,6 1 --------------------------Rb (0.9) 37 Sr (1.0) 38 Cs (0.8) 56Ba (1.0) cesium barium 1 2 ----- 55 Y (1.2) 39 La (1.1) 57 lanthanum 3 --- 40 Sn (1.8) 51Sb (1.9) antimony tin 3, 5 2, 4 -3 --- 50 Au(1.9) 80Hg (1.7) 81Tl (1.6) 82Pb (1.7) 83Bi (1.8) halfnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth 4 5 1, 3 2,3,4,5,6 1,2,4,6,7 2,3,4,6,8 2,3,4,6 3, 5 2, 4 1, 2 1, 3 2, 4 ------------------------Hf (1.3) 72 Ta (1.4) 73 W (1.5) 74 75 Re (1.7) 76Os (1.9) Ir (1.9) 77 78 Pt (1.8) 79 Te (2.1) 52 tellurium 4, 6 -2 I (2.5) iodine 53 1, 5, 7 -1 Po (1.9) 85At (2.1) 84 polonium 2, 4 --- astatine 13 Writing the Formulas of Binary Compounds •Chemical formulas represent the smallest whole number ratio of atoms/ions in a compound. •The positive and negative charges (Ox #’s) must add up to zero; the charges balance. Steps calcium chloride boron bromide 1. Obtain ion symbols & Ox #’s (charges) calcium: Ca+2 hydrogen sulfide magnesium phosphide magnesium: Mg+2 chloride: Cl- B+3 (2.0EN) hydrogen: H+ (2.1EN) bromide: Br - (2.8EN) sulfide: S-2 (2.5EN) 2. Find the total charge needed to balance + & - charges Ca+2 B+3 Mg+2 3. Find the ratio of + and - ions 1 Ca+2 ion for every 2 Cl- ions 4. Use subscripts to write the formulas Cl- = +2 -1 -1 = -2 CaCl2 boron: = +3 H+1 +1 +1 = +2 Br - -1 -1 -1 = -3 S-2 = -2 1 B+3 ion for every 3 Br - ions 2 H+ ions for every 1 S-2 ion BBr3 H2S phosphide: P-3 P-3 +2 +2 +2 = +6 -3 -3 = -6 3 Mg+2 ions for every 2 P-3 ions Mg3P2 Nonmetals such as Cl, Br, H, S and P can have ⊕ or ⊖ Ox #’s. An atom is assigned a ⊕ Ox # when it is the less EN atom in a compound and a ⊖ Ox # when it is the more EN atom in a compound. 14 Practice writing the chemical formulas of binary compounds: name ions formula magnesium oxide potassium nitride Mg+2 O-2 MgO K+ N-3 K3N barium fluoride silicon iodide beryllium carbide Ba+2 F- BaF2 Si+4 I- SiI4 Be+2 C-4 Be2C calcium hydride lithium selenide sodium phosphide Ca+2 H- CaH2 Li+ Se-2 Li2Se Na+ P-3 Na3P zinc phosphide aluminum sulfide boron oxide Zn+2 P-3 Zn3P2 Al+3 S-2 Al2S3 B+3 O-2 B2O3 A chemical formula shows the lowest whole number ratio of ions such that the total positive and negative charges are equal. The ‘Inverse rule’ is an easy way to find this ratio. Consider zinc phosphide. Zn+2 P-3 Zn3P2 The number of Zn cations (3) equals the charge of the anion (-3), and the number of P anions (2) equals the charge of the cation (+2). But remember to reduce this to the lowest whole number ratio. Consider beryllium carbide. Be+2 C-4 Be4C2 Be2C 15 Finding an Ox # in Compounds Containing a Multivalent Ion water = H2O water ≠ HO2 or H3O or HO, etc. because the Ox # H = +1 and Ox # O = -2 In order to combine elements in a chemical formula in the correct ratio, you need to know the Ox #’s of each element. You will also need to know these Ox #’s for writing chemical names. However many elements are ‘multivalent’; they have more than one possible Ox #. Fortunately, it is always true that at least one of the elements in a binary compound will have an Ox # that is known for certain and so the other element’s Ox # can be calculated. Example 1: Manganese has 5 different Ox #’s in its compounds, i.e., +2, +3, +4, +6 and +7. Calculate the Ox # of Mn in MnCl2. Answer: Mn = +2 Here’s why: The Ox # of Cl is -1 because it is more EN than Mn. Chloride is always -1. The total negative charge in MnCl2 = (Cl-1 × 2) = -2. So the total positive charge of Mn must be +2, and the Ox # of Mn must be +2. 16 Example 2: Calculate the Ox # of Mn in Mn2O3 Answer: Mn = +3 Here’s why: The Ox # of O is always -2. The total negative charge of three O’s = (-2 × 3) = -6 The total positive charge of both Mn ions must be +6 (total ⊕ = total ⊖). So each Mn has a charge of (+6/2) = +3 or solve as a math equation: Let Ox # of Mn = x The sum of all Ox #’s = 0 Mn2O3 = 0 (x)*2 + (-2)*3 = 0 2x – 6 = 0 x = +6/2 = +3 Mn+3 or use the Inverse Rule: +3 -2 Mn2O3 17 Practice: Calculate the Ox # of the underlined ion in each formula Formula MnO2 MnO3 Mn2O7 V3N5 Fe4C3 anion charge -2 -2 -2 -3 -4 cation charge Formula anion charge cation charge +4 +6 +7 +5 +3 Cu3P PbF4 PCl5 Mo2S5 NiH3 -3 -1 -1 -2 -1 +1 +4 +5 +5 +3 18 Naming Binary Compounds Containing a Multivalent Ion: Iron (Fe), like manganese (Mn) can exhibit more than one Ox #. There are two kinds of iron chloride, FeCl2 and FeCl3. The name ‘iron chloride’ is thus ambiguous. In binary compounds containing cations with more than one Ox #, the Ox # of the cation is written in Roman numerals (in parentheses) immediately after the cation. Thus FeCl2 is named iron(II) chloride and FeCl3 is named iron(III) chloride. +2 FeCl2 = Fe FeCl3 = Fe+3 - Cl = iron(II) chloride Cl- = iron(III) chloride no space between the cation name and its Ox # but always leave a space immediately before the anion name There are two different forms of iron chloride. Iron(II) chloride is green. Iron(III) chloride is yellow/rusty colored. Each different chemical compound must have its own, unique, unambiguous name. 19 Look at the formulas and names of two kinds of iron oxide, FeO and Fe2O3. Please read carefully: The Ox # listed immediately after the cation indicates the charge on the cation, not necessarily the number of anions in the formula. +2 O-2 FeO = Fe Fe2O3 = Fe+3 = iron(II) oxide FeO is black O-2 = iron(III) oxide The Ox #, e.g., (II) or (III) indicates the charge on the cation, not necessarily the number of anions present. Fe2O3 is rusty/red To name a compound, write the ion symbols and determine their Ox #’s from the combining ratio given in the formula. The anion usually has only one possible Ox #, so calculate the Ox # of the cation remembering that the total ⊕ charge and ⊖ charges in compounds are equal. 20 Naming Binary Compounds Containing a Multivalent Ion: Steps 1. Identify the Ox # that is known for certain (usually the anion’s). Au3N Cl2O5 nitride: N-3 (Group 5A) oxide: O-2 (Group 6A) (N is more EN than Au, so it uses its O is more EN than Cl, negative Ox #) O always has an Ox # of -2 2. If allowed, check the periodic table for the possible charges of the other ion. Au+ or Au+3 Cl+, Cl+3, Cl+5 or Cl+7 3. Determine the ratio of ions in the formula Au3N means 3 gold ions for every 1 nitride ion. Cl2O5 means 2 chlorines for every 5 oxide ions. 4. Find what charge must be on the multivalent ion to balance all charges Au+ +1 +1 +1 = +3 N-3 = -3 3 Au+ ions are needed for every 1 N-3 ion Cl+5: +5 +5 = +10 O 2-: -2 -2 -2 -2 -2 = -10 2 Cl+5 atoms are needed for every 5 O-2 ions. 5. Write the name of the compound gold(I) nitride chlorine(V) oxide 21 Practice Naming Binary Compounds Containing a Multivalent Ion: Determine Ox #’s of the ions in the compounds below. Use these Ox #’s to write Stock system names of the compounds. name formula ions name formula ions iron(II) oxide FeO Fe+2 O-2 iron(III) oxide Fe2O3 Fe+3 O-2 chromium(VI) oxide CrO3 Cr+6 O-2 manganese(IV) sulfide MnS2 Mn+4 S-2 nickel(III) fluoride NiF3 Ni+3 F- cobalt(III) chloride CoCl3 Co+3 Cl- copper(II) oxide CuO Cu+2 O-2 cobalt(II) oxide CoO Co+2 O-2 copper(I) oxide Cu2O Cu+ tin(IV) nitride Sn3N4 Sn+4 N-3 gold(III) bromide AuBr3 Au+3 Br- tin(II) nitride Sn3N2 Sn+2 N-3 O-2 22 Practice Writing Formulas of Binary Compounds Containing Multivalent Ions: name formula ions chromium(III) oxide Cr2O3 Cr+3 O-2 name formula ions cobalt(III) phosphide CoP Co+3 P-3 nickel(II) fluoride NiF2 Ni+2 F- vanadium(V) chloride VCl5 V+5 Cl- titanium(IV) oxide TiO2 Ti+4 O-2 tungsten(IV) carbide WC W+4 C-4 Note: The formula of a binary compounds does not show the charge of the cation or the anion. Do not write any charges in binary compound formulas. For example, sodium chloride’s formula is NaCl, not Na+Cl-. 23 Binary Acids: Binary acids contain hydrogen, H, that is covalently bonded to a non metal. Hydrogen chloride, HCl, is an example of a binary acid. When dissolved in water, hydrogen chloride is named hydrochloric acid because it releases an acidic H+ ion when it ionizes. Learn the names and formulas of the five common binary acids, listed below. name (anhydrous) name (in water) formula reaction in water hydrogen fluoride hydrofluoric acid HF HF H+ + F- hydrogen chloride hydrochloric acid HCl HCl H+ + Cl- hydrogen bromide hydrobromic acid HBr HBr H+ + Br- hydrogen iodide hydroiodic acid HI HI H+ + I- hydrogen sulfide hydrosulfuric acid H2S H2S 2H+ + S-2 24 Summary of Stock System Nomenclature for Binary Compounds SnO tin(II) oxide NaCl sodium chloride SnO2 tin(IV) oxide CaCl2 calcium chloride Cr2O3 chromium(III) oxide Al2O3 aluminum oxide CrO3 chromium(VI) oxide ZnS zinc sulfide CuBr copper(I) bromide Ag3P silver phosphide CuBr2 copper(II) bromide There is > 1 tin oxide, chromium oxide, copper bromide. Sn, Cr, Cu have > 1 Ox # Sn (+2, +4), Cr (+2, +3, +6), Cu (+1, +2) Ox #’s must be included in the name (written in Roman numerals). There is only one sodium chloride, calcium chloride, aluminum oxide, zinc sulfide, and silver phosphide. Na, Ca, Al, Zn, Ag have only 1 Ox # each. Na & Ag (+1), Ca & Zn (+2), Al (+3) The Ox # is not stated in the name. 25 The Prefix System for Binary Compounds For binary compounds containing two non-metals, a Greek or Latin prefix is attached to the name of an element to indicate the number of atoms of that element in the compound. Number 1 2 3 4 5 6 Prefix mono di tri tetra penta hexa Formula CO CO2 SO3 CCl4 PCl5 SF6 Prefix System Name carbon monoxide carbon dioxide sulfur trixode carbon tetrachloride phosphorus pentachloride sulfur hexafluoride 7 = hepta, 8 = octa, 9 = ennea, 10 = deca Although this system is used almost exclusively for non-metal/non-metal compounds, occasionally, it is used when a metal is present. Attach a prefix to the 2nd atom in the formula (always). Attach a prefix to the 1st atom in the formula (only if there is more than one of them). 26 Name the following compounds using both the Prefix system and the Stock system: Formula N2O NO NO2 N2O3 N2O4 N2O5 ICl CS2 SO2 PCl3 P2O5 SCl6 MnO2 Prefix System Name dinitrogen monoxide nitrogen monoxide nitrogen dioxide dinitrogen trioxide dinitrogen tetr(a)oxide dinitrogen pent(a)oxide iodine monochloride carbon disulfide sulfur dioxide phosphorus trichloride diphosphorus pent(a)oxide sulfur hexachloride manganese dioxide Stock System Name nitrogen(I) oxide nitrogen(II) oxide nitrogen(IV) oxide nitrogen(III) oxide nitrogen(IV) oxide nitrogen(V) oxide iodine(I) chloride carbon(IV) sulfide sulfur(IV) oxide phosphorus(III) chloride phosphorus(V) oxide sulfur(VI) chloride manganese(IV) oxide 27 The “Ous-Ic” System For binary compounds in which the cation usually has only 2 oxidation states, the old “ous-ic” system is sometimes used. In a few cases, when the English name of the metal atom is awkward, the Latin name of the metal is used instead. Then the suffix “ous” is added for the lower oxidation number and “ic” for the higher oxidation number. Symbol Cu Fe Pb Sn Au Hg Pt Co Name copper iron lead tin gold mercury platinum cobalt Latin Name cuprum ferrum plumbum stannum aurum ------- Ion Charge & Name Cu+ = cuprous, Cu+2 = cupric Fe+2 = ferrous, Fe+3 = ferric Pb+2 = plumbous, Pb+4 = plumbic Sn+2 = stannous, Sn+4 = stannic Au+ = aurous, Au+3 = auric Hg+ = mercurous, Hg+2 = mercuric Pt+2 = platinous, Pt+4 = platinic Co+2 = cobaltous, Co+3 = cobaltic 28 Name the following compounds using the “ous-ic” system. Formula PbCl2 PbCl4 SnBr2 SnBr4 Cu2O CuO FeO Fe2O3 Au2S3 PtF2 PtS2 Hg4C Hg3N2 Ous-Ic Name plumbous chloride plumbic chloride stannous bromide stannic bromide cuprous oxide cupric oxide ferrous oxide ferric oxide auric sulfide platinous fluoride platinic sulfide mercurous carbide mercuric nitride Stock System Name lead(II) chloride lead(IV) chloride tin(II) bromide tin(IV) bromide copper(I) oxide copper(II) oxide iron(II) oxide iron(III) oxide gold(III) sulfide platinum(II) fluoride platinum(IV) sulfide mercury(I) carbide mercury(II) nitride 29 Peroxides: • A reactive type of compound, called ‘peroxides’, has important commercial and industrial applications. The most familiar example is hydrogen peroxide, H2O2. H2O2 hydrogen peroxide ‘per’ means one more O than the normal oxide. H2O hydrogen oxide H H O • • • • • H O O H H2O2 is one of the strongest oxidizers known. 35 – 50% aqueous solutions are used industrially for pulp and paper bleaching. Up to 12% H2O2 is used as hair bleach and 3% H2O2 is sold as a household disinfectant. Peroxides are unusual, in that the ‘O’ in a peroxide has an Ox # = -1 and the formula of the peroxide anion is written O2-2 (because the peroxide anion is a bonded pair of O’s). Recall that ‘O’ is in Group 6A, it will be stable when it gains 2 electrons and becomes oxide, O-2, so it is not surprising that peroxide, O2-2, is so reactive (unstable). 30 Group 1A and 2A metal peroxides have some interesting applications. For example, sodium peroxide, Na2O2, converts carbon dioxide to oxygen and sodium carbonate. Na2O2 + CO2 Na2CO3 + ½ O2 Both lithium peroxide and sodium peroxide have been used to regenerate oxygen from exhaled air in confined spaces, such as submarines and spacecraft. Peroxide Practice: Write the name or formula of the following compounds. Spelling counts. Formula H2O H2O2 BaO2 K2O2 K2O CaO2 Stock System Name hydrogen oxide (Prefix name: dihydrogen monoxide) hydrogen peroxide barium peroxide potassium peroxide potassium oxide calcium peroxide Ox # & Charges H+ O-2 H+ O2-2 Ba+2 O2-2 K+ O2-2 K+ O-2 Ca+2 O2-2 Note that peroxide formulas, such as H2O2, Na2O2, etc. are not reduced to the lowest whole number ratio. Do not write HO or NaO. All peroxides contain a pair of bonded O’s. Finished Part 1. 31 Congrats, you just completed inorganic chemical nomenclature part 1 on Binary Compounds There is also a second video dealing with the nomenclature of Polyatomic Compounds. Youtube ‘Inorganic Chemical Nomenclature Part 2 Polyatomic Compounds’ 32 Intro to Inorganic Chemical Nomenclature Part 2, Polyatomic Compounds This lesson was divided into two parts Part 2 Polyatomic Compounds • In this video we will study the nomenclature of Polyatomic Compounds • There is also a first video in which I presented the nomenclature of Binary Compounds. You should complete that video first. • Youtube ‘Inorganic Chemical Nomenclature Part 1 Binary Compounds’ 33 Inorganic Nomenclature Part 2 Polyatomic Compounds Oxy Acids: Oxyacids contain H, O and another nonmetal atom. Many oxyacids are commonly found in cleaning products, fruits, food ingredients, industrial chemicals, etc. • • • • Phosphoric acid, H3PO4, is used to pickle steel and is the flavour in root beers and colas. Sulfuric acid, H2SO4, is the electrolyte in the automobile lead-acid battery (35% H2SO4). Carbonic acid, H2CO3, is formed when carbon dioxide, CO2, is dissolved in water (H2O + CO2 H2CO3). Carbonated beverages contain carbonic acid. A 5% solution of acetic acid, CH3COOH, in water is sold as vinegar. 34 Here are eight important oxyacids. Some of these exist with varying numbers of oxygen atoms. The ‘main’ oxyacids, the –ic acids, and their names are highlighted. A Car Acetic Carbonic ic acids per … ic H2CO3 … ic CH3COOH … ous hypo … ous Never Stays Perfectly Nitric Sulfuric Phosphoric HNO3 HNO2 H2SO4 H2SO3 H3PO4 H3PO3 H3PO2 Clean Chloric HClO4 HClO3 HClO2 HClO Bromic HBrO4 HBrO3 HBrO2 HBrO Iodic HIO4 HIO3 HIO2 HIO When oxyacids react, they release hydrogen ions, H+, and leave behind polyatomic anions. HNO3 H+ + NO3and H2SO4 2H+ + SO4-2 and H3PO4 3H+ + PO4-3 A ate anions per … ate … ate … ite hypo … ite Car Never Acetate Carbonate Nitrate CH3COO- CO3-2 NO3NO2- * H3PO3 only has 2 acidic H’s, so phosphite is HPO3-2 Stays Perfectly Clean Sulfate Phosphate SO4-2 SO3-2 PO4-3 * HPO3-2 ** H2PO2- Chlorate ClO4ClO3ClO2ClO- Bromate BrO4BrO3BrO2BrO- Iodate IO4IO3IO2IO- ** H3PO2 only has 1 acidic H, so hypophosphite is H2PO2- 35 Practice: Study the structures and learn the formulas and names of the acids and their anions. +1 -2 + -1 CH3COOacetate CH3COOH acetic acid +1 2 + H2SO4 sulfuric acid SO4-2 sulfate -3 2 +1 + CO3-2 carbonate H2CO3 carbonic acid +1 HNO3 nitric acid -2 + + PO4-3 phosphate H3PO4 phosphoric acid +1 -1 NO3nitrate +1 3 HClO3 chloric acid + -1 ClO3chlorate 36 Practice: Study the Lewis structures and learn the formulas & names of the acids and their anions. H H O C C O H H+ H + H H O C C - H O CH3COOacetate C O H 2H + - O C O H - N+ O O HNO3 nitric acid H H+ - + O NO3nitrate O O O O P O O H Cl O HClO3 chloric acid - SO4-2 sulfate H 3 H+ - + O P O O - - PO4-3 phosphate O - O S O O N+ O + 2 H+ H3PO4 phosphoric acid O- O- H O CO3-2 carbonate H2CO3 carbonic acid O H2SO4 sulfuric acid O + S O O O O O H CH3COOH acetic acid H O H H+ + O Cl O - ClO3chlorate 37 Other Polyatomic Ions: A few other important polyatomic ions are shown below. +1 -1 + CNcyanide HCN hydrocyanic acid -1 +1 OHhydroxide H2O water + NH3 ammonia + +1 +1 NH4+ ammonium HCN, hydrogen cyanide is acidic. In water it is called hydrocyanic acid. Although it is a weak acid and has a sweet almond odour, it is highly toxic when ingested. HCN H+ + CN- The formula of water, H2O, looks like other binary acids, but water is completely neutral. When a H+ ion is removed from water, hydroxide ion, OH-, a strong base is formed. Ammonia, NH3, is a moderately strong base with a pungent odour – the smell of Windex. When NH3 reacts with H+, an ammonium cation, NH4+, is formed: NH3 + H+ NH4+ NH4+ (ammonium ion) is the only polyatomic ion listed that is a cation. Its ‘ium’ ending indicates that it is a cation. The polyatomic anions have endings ‘ate’, ‘ite’, and ‘ide’. 38 Other Polyatomic Ions: A few other important polyatomic ions are shown below. H C H+ N - + C N CNcyanide HCN hydrocyanic acid H+ H O H - + O H OHhydroxide H2O water H H N H NH3 ammonia + H H + H N+ H H NH4+ ammonium HCN, hydrogen cyanide is acidic. In water it is called hydrocyanic acid. Although it is a weak acid and has a sweet almond odour, it is highly toxic when ingested. HCN H+ + CN- The formula of water, H2O, looks like other binary acids, but water is completely neutral. When a H+ ion is removed from water, hydroxide ion, OH-, a strong base is formed. Ammonia, NH3, is a moderately strong base with a pungent odour – the smell of Windex. When NH3 reacts with H+, an ammonium cation, NH4+, is formed: NH3 + H+ NH4+ NH4+ (ammonium ion) is the only polyatomic ion listed that is a cation. Its ‘ium’ ending indicates that it is a cation. The polyatomic anions have endings ‘ate’, ‘ite’, and ‘ide’. 39 Monoprotic and Polyprotic Acids: Acids like CH3COOH, HNO3, HNO2, HClO4, HClO3, HClO2, HClO, etc. have only one ionizable H+ ion per molecule; these are called monoprotic acids. The three H’s bonded to C in CH3COOH are not ionizable. Acids like H2CO3, H2SO4, H2SO3 and H3PO4 can release more than one H+ ion per molecule; they are called polyprotic acids because they can release more than one H+ (proton). When polyprotic acids lose some but not all of their ionizable H’s, important polyatomic anions form. H2CO3 HCO3- H2SO4 HSO4- H2SO3 HSO3- H3PO4 H2PO4- HPO4-2 H+ H+ H+ H+ H+ H+ H+ H+ H+ + + + + + + + + + HCO3CO3-2 HSO4SO4-2 HSO3SO3-2 H2PO4HPO4-2 PO4-3 bicarbonate or monohydrogen carbonate carbonate bisulfate or monohydrogen sulfate sulfate bisulfite or monohydrogen sulfite sulfite dihydrogen phosphate monohydrogen phosphate phosphate 40 The stepwise ionization of some polyprotic acids is shown. O H O O P O O H H+ H H3PO4 phosphoric acid + H O H O P O O H - H P O O H H+ - + H O O - O O P O O - HPO4-2 monohydrogen phosphate H + - O P O H H+ + H O S O S O HSO4bisulfate O O H+ - - + O S PO4-3 phosphate O SO4-2 sulfate O O H O S - O HSO4bisulfate - - - O O O O + H - HPO4-2 monohydrogen phosphate - O O P O S H2SO4 sulfuric acid O H2PO4dihydrogen phosphate H O O H2PO4dihydrogen phosphate O O O O H2SO3 sulfurous acid H H+ + H O S O - HSO3bisulfite 41 Formulas and Names Involving Polyatomic Ions: Compounds containing polyatomic ions are named the same as binary compounds. Formulas containing polyatomic ions are written the same as binary compounds, with one difference … sodium chloride is NaCl calcium chloride is CaCl2 Parentheses are not placed around monatomic ions like Cl-, even when several are present in the formula. sodium hydroxide is NaOH calcium hydroxide is Ca(OH)2 Parentheses are placed around polyatomic ions like OH-, only when several are present in the formula. Ammonium hydroxide, NH4OH, contains two polyatomic ions, the ammonium cation, NH4+, and the hydroxide anion, OHIn ammonium cyanide, NH4CN, the N atom occurs twice. They remain separate so that the both the ammonium cation, NH4+, and the cyanide anion, CN-, are recognized. 42 Practice: Write names or formulas in the empty cells. Use the Stock System. Formula Zn(C2H3O2)2 Fe(C2H3O2)3 Cr(NO2)6 Mn(NO3)7 Al2(SO4)3 Al(HSO4)3 K2SO3 Fe(HSO3)2 Ni(ClO4)2 Sn(ClO3)2 Pb(ClO2)4 HgBrO Co(BrO3)3 Cr(BrO4)3 Name zinc acetate iron(III) acetate chromium(VI) nitrite manganese(VII) nitrate aluminum sulfate aluminum bisulfate potassium sulfite iron(II) bisulfite nickel(II) perchlorate tin(II) chlorate lead(IV) chlorite mercury(I) hypobromite cobalt(III) bromate chromium(III) perbromate ions & Ox #’s Zn+2 CH3COOFe+3 CH3COOCr+6 NO2Mn+7 NO3Al+3 SO4-2 Al+3 HSO4K+ SO3-2 Fe+2 HSO3Ni+2 ClO4Sn+2 ClO3Pb+4 ClO2Hg+ BrOCo+3 BrO3Cr+3 BrO443 Practice: Write names or formulas in the empty cells. Use the Stock System. Formula Sr(IO2)2 (NH4)2SO4 LiIO Be(IO3)2 Cu(BrO2)2 Al2(CO3)3 Cu(HCO3)2 Ba3(PO4)2 Cd(IO4)2 W(CN)6 Mo(CO3)3 V2(SO3)5 Pt3(PO4)4 Hg(HSO4)2 Name strontium iodite ammonium sulfate lithium hypoiodite beryllium iodate copper(II) bromite aluminum carbonate copper(II) bicarbonate barium phosphate cadmium periodate tungsten(VI) cyanide molybdenum(VI) carbonate vanadium(V) sulfite platinum(IV) phosphate mercury(II) bisulfate ions & Ox #’s Sr+2 IO2NH4+ SO4-2 Li+ IOBe+2 IO3Cu+2 BrO2Al+3 CO3-2 Cu+2 HCO3Ba+2 PO4-3 Cd+2 IO4W+6 CNMo+6 CO3-2 V+5 SO3-2 Pt+4 PO4-3 Hg+2 HSO444 In most oxyacids, adding or subtracting O’s to a formula does not change the number of ionizable H’s. HNO3 and HNO2 are both monoprotic acids. H2SO4 and H2SO3 are both diprotic acids. HClO4, HClO3, HClO2 and HClO are all monoprotic acids. The oxyacids of P are unique. H3PO4 is triprotic, but H3PO3 is only diprotic, and H3PO2 is monoprotic. Examine the structures of these oxyacids and note that acidic H’s are bonded to O, not to P. O H O acidic H O P O O H H3PO4 phosphoric acid triprotic H H O acidic H bonded to O P O H O H H H3PO3 phosphorous acid diprotic P O H H nonacidic H not bonded to O H3PO2 hypophosphorous acid monoprotic 45 O H O O P O O H H H3PO4, phosphoric acid - H+ H O O P O O H - H+ - H O P O H2PO4-, dihydrogen phosphate O O - H+ - - O P - O HPO4-2, monohydrogen phosphate O - - PO4-3, phosphate Because phosphorous acid (H3PO3) has only two ionizable H’s, HPO3-2 is fully ionized and can be named monohydrogen phosphite or simply ‘phosphite’. O H O P O - H H O O + H H O P O - - H+ - O P - H H HPO3-2, monohydrogen phosphite or simply ‘phosphite’ H2PO3-, dihydrogen phosphite H3PO3, phosphorous acid O Because hypophosphorous acid (H3PO2) has only one ionizable H, H2PO2- is fully ionized and can be named dihydrogen hypophosphite or simply ‘hypophosphite’. O O H P O H H H3PO2, hypophosphorous acid H+ + H P O - H H2PO2-, dihydrogen hypophosphite or simply ‘hypophosphite’ 46 As we are seeing, there are several conventions for naming the anions of partly ionized polyprotic acids. The student has latitude here, however, any correct name must identify the compound unambiguously. Try naming the following compounds using more than one correct name. Formula H3PO4 NaH2PO4 K2HPO4 LiH2PO3 Ag2HPO3 NaH2PO2 (NH4)2HPO4 (NH4)2HPO3 NH4H2PO4 (NH4)2KPO4 Name phosphoric acid or hydrogen phosphate sodium dihydrogen phosphate or monosodium phosphate potassium monohydrogen phosphate or dipotassium phosphate lithium dihydrogen phosphite or monolithium phosphite silver monohydrogen phosphite or silver phosphite sodium dihydrogen hypophosphite or sodium hyposphosphite diammonium monohydrogen phosphate or diammonium phosphate diammonium monohydrogen phosphite or ammonium phosphite ammonium dihydrogen phosphate or monoammonium phosphate diammonium potassium phosphate ions & Ox #’s H+ PO4-3 Na+ H2PO4K+ HPO4-2 Li+ H2PO3Ag+ HPO3-2 Na+ H2PO2NH4+ HPO4-2 NH4+ HPO3-2 NH4+ H2PO4NH4+ K+ PO4-3 The number of H’s need not be stated, provided the number of other cations is explicitly stated in the name. Prefixes like ‘di’ or ‘tri’ should only be used when partially ionized polyprotic acids are being named. 47 For compounds of monovalent cations (Li+, Na+, K+, NH4+, etc.) we have seen that there are several acceptable names … e.g., K2HPO4 = dipotassium monohydrogen phosphate or potassium monohydrogen phosphate or dipotassium phosphate However, when polyvalent cations, like Ca+2, Al+3, etc. are combined with partially ionized acids, the convention is to state the number of H’s but not the number of polyvalent metal cations, as follows … Ca(H2PO4)2 CaHPO4 Al(H2PO4)3 Al2(HPO4)3 Fe2(HPO4)3 SnHPO4 Pb(H2PO3)4 Pd(H2PO2)4 Pd(H2PO2)2 calcium dihydrogen phosphate calcium monohydrogen phosphate aluminum dihydrogen phosphate aluminum monohydrogen phosphate iron(III) monohydrogen phosphate tin(II) monohydrogen phosphate lead(IV) dihydrogen phosphite palladium(IV) dihydrogen hypophosphite or palladium(IV) hypophosphite palladium(II) dihydrogen hypophosphite or palladium(II) hypophosphite Ca+2 Ca+2 Al+3 Al+3 Fe+3 Sn+2 Pb+4 Pd+4 Pd+2 H2PO4HPO4-2 H2PO4HPO4-2 HPO4-2 HPO4-2 H2PO3H2PO2H2PO248 Practice: Write the name or formula of the following compounds. Spelling counts. The column on the right will not be marked. Formula Mg(CH3COO)2 (NH4)2SO4 Fe2(CO3)3 Ba(NO3)2 Mn(ClO2)7 Cd(IO4)2 AlH3 Be3N2 Hg(BrO)2 H2SO3 HClO3 (NH4)2HPO4 Zn(H2PO2)2 Stock System Name magnesium acetate ammonium sulfate iron(III) carbonate barium nitrate manganese(VII) chlorite cadmium periodate aluminum hydride beryllium nitride mercury(II) hypobromite sulfurous acid chloric acid ammonium monohydrogen phosphate or diammonium phosphate zinc dihydrogen hypophosphite or zinc hypophosphite Ox # & Charges Mg+2 CH3COONH4+ SO4-2 Fe+3 CO3-2 Ba+2 NO3Mn+7 ClO2Cd+2 IO4Al+3 HBe+2 N-3 Hg+2 BrOH+ SO3-2 H+ ClO3NH4+ HPO4-2 Zn+2 H2PO249 Other Common Acids: A few other inorganic acids are commonly encountered in the laboratory. Study the structures and names of these acids and their anions. O O Mn O H+ H + O O Mn permanganate, MnO4- O O Cr O H 2 H+ - + O Cr O Cr O O - O chromate, CrO4-2 chromic acid, H2CrO4 O Chromic acid, H2CrO4, is a diprotic acid and strong oxidizer. Its potassium salt, potassium chromate, K2CrO4, is used as an indicator for measurement of chloride by silver nitrate titration. Cr is in its highest oxidation state, +6, (which contributes to its strength as an oxidizer). O O H - O O permanganic acid, HMnO4 H Permanganic acid, HMnO4, is monoprotic. Its potassium salt, potassium permanganate (KMnO4) is a dark purple-colored reagent that is often used in the lab as a strong oxidizing titrant. Mn is in its highest oxidation state, +7, (which contributes to its strength as an oxidizer). O O O O Cr O O dichromic acid, H2Cr2O7 H 2 H+ + - O Cr O O O Cr O - O dichromate, Cr2O7-2 Dichromic acid, H2Cr2O7 is another strongly oxidizing diprotic acid. Its potassium salt, potassium dichromate ( K2Cr2O7) is a common lab reagent. Can you calculate the Ox # of Cr in it? 50 Potassium permanganate, KMnO4, is a very dark purple, crystalline solid. The permanganate ion, MnO4-, is released when dissolved in water, giving rise to bright purple solutions. Potassium chromate, K2CrO4, is a bright yellow, crystalline solid. Aqueous solutions of this reagent are bright yellow owing to the presence of the chromate ion, CrO4-2. Bright orange potassium dichromate, K2Cr2O7, when dissolved in water, releases the dichromate ion, Cr2O7-2. 51 Practice: Write the name or formula of the following compounds. Spelling counts. Formula Fe(MnO4)3 Ag2CrO4 ZnCr2O7 Al2(CrO4)3 Na2Cr2O7 V2(Cr2O7)5 Mn2(SO4)7 Cr(PO4)2 Mo(MnO4)6 Cd(IO4)2 Co(BrO3)3 Ni(ClO2)2 Mg(BrO)2 Almost Finished Stock System Name iron(III) permanganate silver chromate zinc dichromate aluminum chromate sodium dichromate vanadium(V) dichromate manganese(VII) sulfate chromium(VI) phosphate molybdenum(VI) permanganate cadmium periodate cobalt(III) bromate nickel(II) chlorite magnesium hypobromite Ox # & Charges Fe+3 MnO4Ag+ CrO4-2 Zn+2 Cr2O7-2 Al+3 CrO4-2 Na+ Cr2O7-2 V+5 Cr2O7-2 Mn+7 SO4-2 Cr+6 PO4-3 Mo+6 MnO4Cd+2 IO4Co+3 BrO3Ni+2 ClO2Mg+2 BrO52 Name the following compounds using the “ous-ic” system. Formula PbCl2 PbCl4 SnBr2 SnBr4 Cu2O CuO FeO Fe2O3 Au2S3 PtF2 Pt(NO3)4 Hg(ClO4)2 Hg2SO3 Ous-Ic Name plumbous chloride plumbic chloride stannous bromide stannic bromide cuprous oxide cupric oxide ferrous oxide ferric oxide auric sulfide platinous fluoride platinic nitrate mercuric perchlorate mercurous sulfite Stock System Name lead(II) chloride lead(IV) chloride tin(II) bromide tin(IV) bromide copper(I) oxide copper(II) oxide iron(II) oxide iron(III) oxide gold(III) sulfide platinum(II) fluoride platinum(IV) nitrate mercury(II) perchlorate mercury(I) sulfite 53 Congrats, you just completed inorganic chemical nomenclature part 2 on Polyatomic Compounds There is also a previous video dealing with the nomenclature of Binary Compounds. Youtube ‘Inorganic Chemical Nomenclature Part 1 Binary Compounds’ 54