Handbook of Analytical Chemistry

Table of contents :
Front Cover
Title PAge
Contents
Preface
Preliminary Remarks
Table 1 Atomic Weights of the Elements
Table 2 Radioactive Elements
Table 3 Ion Radii
Table 4 Ionization Potentials of Atoms and Ions
Table 5 Structure of Outer Electron Layers
Table 6 Atomic Weights, Molecular Weights*, Weights of Atomic Groups, and Their Logarithms
Table 7 Analytical and Stoichiometric Multipliers (Factors)*
Table 8 Solubilities of Inorganic and Some Organic Compounds
Table 9 Solubilities of Some Inorganic Compounds
Table 10 Solubility Products of the Chief Sparingly Soluble Substances
Table 11 Activity Coefficients of Various Ions
Table 12 Activity Coefficients of Various Ions at High Values of the Ionic Strength of a Solution
Table 13 Calibration of Glassware
Table 14 Calculation of the Results of Volumetric-Analytical Determinations*
Table 15 Masking Reagents in Titration with Complexone III
Table 16 Calculation of the Results of Gas and Gasometric Analyses*
Table 17 Conversion Formulas for Solution Concentrations
Table 18 Densities and Concentrations of Solutions
Table 19 Chief Acid-Base Indicators*
Table 20 Ionic Product of Water at Temperatures Ranging from 0 °C to 100 °C
Table 21 Colorimetric Determination of pH of Solutions
Table 22 Ionization Constants Qf indicators (pKi; at different ionic strength)
Table 23 Some Mixed Indicators
Table 24 Universal Indicators
Table 25 Chief Fluorescent Indicators
Table 26 Selected Chemiluminiscent Indicators
Table 27 Principal Adsorption Indicators
Table 28 Indicators Commonly Used in Complexonometry
Table 29 Hydrogen Ion Exponent (pH) Evaluated
Table 302 Preparation of Buffer Solutions
Table 31 Acetic-Acetate Buffer Solutions
Table 32 Universal Buffer Mixture
Table 33 Buffer Solutions from Individual Substances
Table 34 Determination of Electrode Potentials
Table 35 Electrometric Determination of pH
Table 36 Change of pH in Precipitation of Metal hydroxides
Table 37 Ionization Constants of Chief Acids and Bases
Table 38 Dissociation Constants of Complex Ions
Table 39 Mobility of Selected Ions at 25 C and Infinite Dilution
Table 40 Standard Oxidizing Potentials (E °) Relative tothe Potential of a Standard Hydrogen Electrode* at 25 °C
Table 41 Chief Oxidation-Reduction Indicators
Table 42 Spectral Wavelengths and Colours Corresponding to Them
Table 43 Photometric Methods of Determining Various Ions
Table 44 Properties of Selected Solvents
Table 45 Extraction with Organic Solvents
Table 46 Separation of Organic Compounds
Table 47 Substances Used for Drying
Table 48 Preparation of Hygrostats
Table 49 Principal Organic Reagents
Table 50 USSR Standard Sieves
Table 51 Half-Wave Potentials in Polarographic Analysiswith a Dropping Mercury Electrode
Table 52 Amperometric Titration of Selected Substances
Table 53 Conditions of Amperometric Titration with Two Polarized
Table 54 Overvoltage of Hydrogen and Oxygen atVarious Electrodes
Table 55 Potentials of Electrode Decomposition of 1N Solutions of Selected Compounds
Table 56 Flame Photometry
Table 57 British and American Weights and Measures in Comparison with the Metric System of Measurement
Table 58 Simplified Table of Five-Place Logarithms
Appendices Examples of Using Some Tables
Index

Citation preview

Ju. L U R I E

Handbook of Analytical Chemistry

Mi l !

P r It 1.1 S II K K S M () S C O \Y

K). HD. Jlypbe C nP A B O H H H K

n o AHAJIHTHHECKOn XHM HH M3AaTejiLCTBO

Ju. LURI E

Handbook of Analytical Chemistry T ranslated from th e R ussian by N icholas Bobrov

MIR PU B L ISH E R S MOSCOW

F irst published 1975 Second printing 1978

Ha amAutLcKOM mukc

©

English translation, Mir Publishers, 1975

TO THE READER Mir Publishers welcome your comments on the content, translation and design of this book. We would also be pleased to receive any proposals you care to make about our future publications. Our address is: USSR, 129820, Moscow 1-110, GSP Pervy Rizhsky Pereulok, 2 Mir Publishers

Printed in the Union of Soviet Socialist Republics

Contents

P re fa c e .............................................................................................. Preliminary Remarks .................................................................. Table 1. Atomic Weights of the E le m e n ts................................... Table 2. Radioactive E le m e n ts.................................................. Table 3. Ion R a d i i ...................................................................... Table 4. Ionization Potentials of Atoms and I o n s .................... Table 5. Structures of Outer Electron Layers, Ion Potentials and Analytical Groups of C atio n s............................................... Table 6. Atomic Weights, Molecular Weights, Weights of Atomic Groups, and Their L ogarithm s........................................... Table 7. Analytical and Stoichiometric Multipliers (Factors) Table 8. Solubilities of Inorganic and Some Organic Compounds in W a t e r .................................................................................. Table 9. Solubilities of Some Inorganic Compounds in Organic Solvents at 18-25 ° C .............................................................. Table 10. Solubility Products of the Chief Sparingly Soluble S u b s ta n c e s .............................................................................. Table 11. Activity Coefficients of Various I o n s ....................... Table 12. Activity Coefficients of Various Ions at High Values of the Ionic Strength of a S o l u t i o n ....................................... Table 13. Calibration of G la s s w a re ........................................... Table 14. Calculation of the Results of Volumetric-Analytical D e te rm in a tio n s...................................................................... A. Acid-Base Titrations . . ............................................... B. Oxidation-Reduction Methods . . . • ....................... C. Methods of Precipitation and C o m p le x in g ................ D. Methods' of Titration with Complexone III . . . . . Table 15. Masking Reagents in Titration with Complexone III Table 16. Calculation of the Results of Gas and Gasometric AnaA. Bringing the Gas Volume to Standard Conditions . . B. Vapour Pressure over Water and over Absorbing Solu­ tions .................................................................................. C. Densities of Gases and Vapours ( p ) ................................

9 11 17 21 22

27 30 31 70 76 100

105 117 120 121

123 123 125 129 130 132 136 138 155 156

G D. Gasometric (Volumetric) Determination of Gas-Form­ ing S u b sta n c e s .................................................................... 158 Table 17. Conversion Formulas for Solution Concentrations 159 Table 18. Densities and Concentrations of S o lu tio n s ................ 100 A. Densities and Concentrations of Nitric Acid Solutions 160 13. Densities and Concentrations of Sulphuric Acid Solu­ tions 161 C. Densities and Concentrations of Hydrochloric Acid S olutio n s................................................................................ 164 D. Densities and Concentrations of Phosphoric Acid Solu­ tions .................................................................................... 165 E. Densities and Concentrations of Perchloric Acid Solu­ tions . . . . . . . . 167 F. Densities and Concentrations of Acetic Acid Solutions 169 G. Densities and Concentrations of Potassium Hydroxide S o l u t i o n s ............................................................................ ■ 169 H. Densities and Concentrations of Caustic Soda Solutions 171 I. Densities and Concentrations of Ammonia Solutions . . 172 J. Densities and Concentrations of Sodium Carbonate Solu­ tions 173 K. Densities and Concentrations of Selected Commercial Reagents' . . . 174 Table ID. Chief Acid-Baso I n d ic a to r s ........................................ 176 Table 20. Ionic Product of Water at Temperatures Ranging from 0°C to 100 CC ................................................................ 108 Table 21. Colorimetric notermiiifltion of tlio [ill of Solutions Table 22. Ionization Constants of In d ic a to rs ............................ A, Monochromatic In d ic a to rs ................................................. B. Dichromatic I n d ic a to r s ..................................................... Table 23. Some Mixed Indicators Table 24. Universal Indicators .................................................... Table 25. Chief Fluorescent I n d ic a to r s ........................................ Table 26. Selected Chemiluminescent I n d ic a to r s .................... Table 27. Principal Adsorption I n d ic a to r s ................................ Table 28. Indicators Commonly Used in Complexonometry . . Table 29. Hydrogen Ion Exponent (pH) Evaluated in Terms of the Activity of Hydrogen Ions (aH+) and Vice Versa . . . Table 30. Preparation of Buffer S o lu tio n s .................................... A. Buffer Solutions with pH 1.10-3.50 ............................... B. Buffer Solutions with pH 1.10-4.96 .............................. C. Buffer Solutions with pH2.20-3.80 .............................. D. Buffer Solutions with pH4.00-6.20 .............................. 2 u2 er Soluti°ns with pH4.96-6.69 ......................... ? ufi er Solutions with pH4.80-8.00 G. Buffer Solutions with pH 7.71-9.23

19S 200 200 200 201 203 204 214 216 220 252 253 253 254 255 256 257 257 258

7 II. Buffer Solutions with pH 9.23-11.02 I. Buffer Solutions with pH 8.53-12.90 ............................ Table 31. Acetic-Acetate Buffer S o lu tio n s................................ Table 32. Universal Buffer M ix tu r e ........................................... Table 33. Buffer Solutions from Individual Substances . . . . Table 34. Determination of Electrode P o te n tia ls .................... A. Values of O at n — 1 and Temperatures Hanging from 0 rC to 50 CC ....................................................................... B. Composition and Potential of Selected Reference Electrodes Relative to the Standard Hydrogen Electrode Table 35. Electrometric Determination of p H ........................ A. Standard Quinhydrone Electrode Potential (£qUin./hydr.) at Temperatures Ranging from 0 °C to 50 ° C ................ B. Potentials of Calomel Electrodes at Temperatures Ranging from 0 °C to 50 ° C ........................................... C. Difference between the Standard Quinhydrone Electro­ de Potential (£ °uin /hydr.) and the Potentials of the Reference Calomel Electrodes (£ ce ) at Temperatures Ranging from 0 °C to 50 ° C ........................................... Table 36. Change of pH in Precipitation of Metal Hydroxides T a b l e 3 7 . I o n i z a t i o n C o n s l n n l n of C h i e f Atticls a n d Oftses

.

.

.

Table 38, Dissociation Constants of Complex I o n s .................... Table 39. Mobility of Sol petrel Inns at 25 °C and Infinite Dilu­ tion .......................................................................................... Tahb 40. rttanclnrA Oxidizing Potentials (£») Relative to the Po­ tential Of a standard Hydrogen Electrode at 25 "C . . . .

259 260 262 263 261 265 267 268 269 270 271

272 273 274 283 299

Table 41. Chief Oxidalion-Hoduction indicators.................

300 314

A . In d icators n ot S e n sitiv e to Changes in th e p l l and the Io n ic Strength of a S o lu tion . . . . . . . . . . . .

314

B. Indicators Sensitive to a Change m the pH and the Ionic Strength of a S olution............................................ Table 42. Spectral Wavelengths and Colours Corresponding to T h e m .......................................................................................... Table 43. Photometric Methods of Determining Various Ions Table 44. Properties of Selected S o lv e n ts................................ Table 45. Extraction with Organic S o lv e n ts............................ A. Extraction of Various Elements in the Form of Dithiz o n a t e s ....................... • • • • : • • • • • • • • • • B. Extraction of Various Elements in the Form of Diethyl Dithiocarhamates . . . . . . . . . . . . . . . . . C. Extraction of Various Elements in the Form of Cupferronates . . • •. • • • • • • •. • • • • • • • • ,• • D. Extraction of Various Elements m the Form of Hydroxyquinolates > ............................................

316 320 321 332 336 336 340 343 344

8 E. Extraction of Various Elements from Hydrochloric, Hydrobromic, Hydroiodic and Nitric Acids by an Equal Volume of Diethyl E t h e r ................................................ Table 46. Separation of Organic C om pounds........................... A. Classification of Individual Compounds According to Their Behaviour under the Action of Some Reagents B. Composition of G ro u p s ................................ ... C. Various Organic Compounds Belonging to the Main G r o u p s ............................................................................... D. Widespread Compounds Whose Belonging to a Group Is Difficult to F o r e s e e ................................................... E. Separation of Mixtures ................................................... Table 47. Substances Used for D r y i n g ....................................... A. Drying of G a s e s ............................................................... B. Drying of Liquids ........................................................ Table 48. Preparation of H y g ro s ta ts ....................................... Table 49. Principal Organic R e a g e n ts ....................................... A. In the Alphabetical Order of the Reagents .................... B. In the Alphabetical Order of the Elements Being Deter­ mined ................................................................................... Table 50. USSR Standard S i e v e s ............................................... Table 51. Half-Wave Potentials in Polarographic Analysis with a Dropping Mercury E le c tr o d e .................................... Table 52. Amperometric Titration of Selected Substances . . Table 53. Conditions of Amperometric Titration with Two Po­ larized Indicator Electrodes ............................................... Table 54. Overvoltage of Hydrogen and Oxygen at Various Elec tr o d o s .............................................. ’ .................. Table 55. Potentials of Electrode Decomposition of 1N Solu­ tions of Solectod C om pounds................................................ Table 56. Flame P h o to m e try ........................................................ Table 57. British and American Weights and Measures in Com­ parison with the Metric System of M easu rem en t................ Table 58. Simplified Table of Five-Place Logarithms . . . . A. L ogarithm s............................................................... • • •• B. A ntilog arith m s.................................................................... Appendices. Examples of Using Some T a b le s ............................ Table 7 ................................................................................... Table 1 4 .................................................................................... Table 1 6 .................................................................................... Table 1 8 .................................................................................... Table 1 9 ................................................................................... Table 2 1 ................................................................................... Table 40 ................................................................................... Index ........................ - ...................................................................

346 347 347 348 351 352 356 358 358 358 359 360 360 398 402 403 408 426 442 444 445 446 448 448 454 460 460 462 468 470 472 473 476 480

Preface

Handbook of A nalytical Chemistry is intended for scientific workers, and chemistry students in universities, polytechnics, and technical colleges. It can be used in solving various problems (both calculating and experimental) concerning general chemistry, analytical chemistry, chemical technology, and so forth. The tables of solubility products, of ionization constants of weak acids and bases, and of oxidation-reduction potentials have been drawn up according to recent data. When those tables were being drawn up, the following works were used: J. Bjerrum, G. Schwarzenbach, L. G. Sillen, Stability Constants of Metal-ion Complexes, with Solubility Products of I norganic Substances, London, 1958; W. M. Lati­ mer, The Oxidation States of the Elements and Their Potentials in Aqueous Solutions, N.Y., 1952; N. V. Axelrud and Ya. A. Fialkov, Ukrainskii khimicheskii- diurnal, 16, 75, 283, 296 (1950), and other articles from Soviet and foreign journals. As we know, tho results published by various authors concerning the determination of given quantities greatly differ from one another. It is thoroforo oxlromoly difficult to select, the “most probable” value of every constant. There is no international body to annually publish such “most probable” values of tho givon constants, as is done, for instance, by the International Commission concerning atomic weights. The selection I have made from numerous literary data is therefore inevitably subjective. I will be very grateful for information pointing out cases when this selection was made incorrectly, and will take account of such comments in the subsequent publications of the book. The tables of the densities and concentrations of various acids and bases aro drawn up for 20 °C. The temperature values in all tables are given in degrees Celsius (°C). Tables 22, 32, 33, 34B, 35, 39, 47, 48, 51-55 have been compiled by P. K. Agasyan, docent of the analytical chemistry department of the Moscow State University.

10 Instead of the ordinary table of live-place logarithms, a “simplilied” table of five-place logarithms and antilogarithms is given at the end of the book. It takes up the same space as the tables of four-place logarithm s, because instead of the real values of the differences be­ tween mantissas, their mean values arc given for every line of the table. Errors that arise when using this table arc not over 0.0001)2. The other tables in the handbook give exact values of the live-place mantissas of logarithms. Ju. Ju. Lurie

Preliminary Remarks

The numerical expression of the results^ of weighings and other measurements, and the subsequent calculations with these numbers necessitate a strict observance of several rules. R u l e 1. A ll numerical values, whether they are obtained directly by measurements or whether they are the derivatives of these measurements, must have a certain number of significant digits so that the last figure alone is questionable; the second-last figure must be accurate. For instance, the number 20.24 (ml), which expresses the reading of an ordinary burette, contains a proper number of figures, since figure 4 was obtained by an approximate (visual) estimate of the distance between the edge of the meniscus and the nearest scale divi­ sion. Consequently, this figure is dubious: another observer could read the measurement of the burette as 20.23 or 20.25 ml. If upon measuring the solution by a burette, the lower boundary of the menis­ cus exactly touches the scale division showing 15 ml, the measurement result must be expressed by the number 15.00 (ml), since the observa­ tion error is not over 0.01-0.02 ml. Both zeroes in the number 15.00 (ml) will be significant digits. The zeroes standing at the begin­ ning of the number before the first figure which is not a zero are not regarded as significant digits. Hence, the number expressing the mass of the filter ash 0.00004 (g) contains only one significant digit: 4. IT the mass is determined in grams and expressed by the number 23.4 (g) in which the last figure is inaccurate, in order to represent this mass in milligrams one must write not 23 400 mg, which would give a wrong idea about the accuracy of the weighing, but 234 -102 mg, or 2.34-104 mg. R u l e 2. When discarding the last figure if it is equal to or more than 5, the preceding figure must be increased by unity. Thus, in discarding the last figure in the number 16.236, we obtain 16.24. R u l e 3. Upon addition (and subtraction) of several numbers, there will remain , as a result of calculation, a certain number of figures after the point that are in the addend with the least number of decimals. R u l e 4. Upon multiplication or division , the maximum relative error of the product or quotient cannot be less than the relative error in the least accurate number from the numbers taken. Relative errors are usually expressed in per cent: it is the ratio of the maximum possible error of the number to the number itself multiplied by 100.

12 If, for instance, it is necessary to multiply 0.0123 *24.62-1.07461 and if it is taken th at the maximum absolute error in each of these numbers is not over unity in the last figure, then the corresponding relative errors will be: 133 100 = 0.8% ^

100 = 0.04%

107 461 100 = 0 -001% The first number has the greatest relative error (0.8%). It follows that the maximum relative error is not less than 0.8 per cent in the product as well. If the first three significant digits 0.325 are kept in the product, the last digit will already bo inaccurate, since 0.8 per cent from 0.325 comes to about 0.003. In cases when rule 1 is observed, i.e., when all numbers used in the calculation contain not more than one inaccurate figure, it is possible to apply the more simple (although less accurate) rule 4,a. R u l e 4f Cl. Upon multiplication and division , as a result of calcula­ tion, it is necessary to keep a certain number of significant digits which are in the number having these digits least of all among the numbers used in the calculation . In the example given above, the first cofactor has three, the second has four, and the third has six significant digits. Consequently, wo must leave in the product three significant digits and discard tho rest; the result will be 0.325. R u l e 5 . In all the intermediate results, it is necessary to keep one figure more than is required by the preceding rules . In the final result, this “reserve figure” is discarded. R u l e 6 . I f some data have more decimals (upon addition and subtrac­ tion) or more significant digits (upon multiplication and division) than others, they must first be rounded, keeping one extra figure (see rule 5). R u l e 7 . Upon multiplication and division with the aid of logarithms, it is sufficient to have as many figures in the mantissas as there are signi­ ficant digits in the least accurate multiplier. Therefore, for most calculations, we can confine ourselves to the logarithmic table on page 448 of this book. Together with an excessive as well as an unsubstantiated accuracy of calculations (a long series of figures after the decimal point, when already the first one of them is dubious, the use of multi-place loga­ rithmic tables, and so forth), another error is very common: tho unnecessary accuracy of individual measurements th at leads to the finding of figures which in any case will be discarded upon subsequent calculations (if these calculations are made correctly). Analytical chemists, for instance, have grown accustomed to making all weighings on an analytical balance with an accuracy of up to 0.0001 g, ana they spent much time sitting by the balance, determining the correct figure in the fourth decimal. At the same time, this accuracy is often pointless. Here are a few examples:

13 1. Antimony is determined in red copper in which the Sb content is not more than 0.003%. For analysis, a portion of copper weighing 10 g is taken. With what accuracy must the copper shaving be weighed? The result obtained must have not more than two significant digits, since copper containing even 0.0031% Sb must be discarded. Great accuracy is not needed, and in essence it is unattainable by the analytical methods us'ed. Hence, the maximum absolute error in the final result is ±0.0001%, which makes up ±3.3% of the maximum permissible Sb content in the metal. The calculation is made by the formula

where a = antimony content found; g = weighed portion. If a weighed portion of copper is taken with an accuracy of up to one-tenth of a gram (±0.1 g), then with respect to the entire portion weighing 10 g, the relative error will be ± 1% , which is far less than ±3.3% . In other words, if instead of 10 g of copper, 9.9 g or 10.1 g fire weighed then with a Sb content of 0.30 mg, this will give, in the first case 0.00303% and, in the second case, 0.00297%, which in both cases will be rounded off to 0.0030%. It follows that a weighing can be made on technical scales with an accuracy of up to 0.1 g. 2. The accuracy of the colorimetric methods of analysis (if the optical density of solutions is measured visually and not photocolorimetrically or spectrophotometrically) is usually not over ±5% of the relative errors, while by some other methods, the relative error comes to ±10% and more. According to rule 4, the accuracy of the result cannot be higher than the accuracy of the least accurate measurement, and therefore, no matter how accurately a test is weighed for analysis, if this analysis ends with a colorimetric determination, the accuracy of the results will not be higher than the aforementioned ± 5 % . It follows that if 1 g of a tost is weighed with an accuracy of ±0.01 g, i.e., with a maximum relative error of ± 1% , this accuracy is high enough. Visual colorimetric methods are used only to determine the compo­ nents contained in very small amounts in the substance being analysed, when a great relative error is permissible in the result obtained. The determination of iron in iron ore by the visual colorimetric method leads to impermissible errors. N o te . It must not be assumed that, in determining small amounts, the colorimetric methods of analysis are less accurate than other methods. On the contrary, if in the preceding example Sb is determined not by the. colorimetric method (as is usually done), but by the gravimetric method, we would have to weigh about 0.0003 g of SboO.!, which on an ordinary analytical balance can scarcely be made with a maximum error less than ±30% of the relative errors. In addition, no account is taken of the inevitable significant error due to impurities present in the calcined precipitate, an error which cannot be eliminated even wlien a microbalance is used.

14 3. In the calculation of the results of volumetric-analytical deter­ minations, the least accurate figure is the number of millilitres of a titrating solution used for titration. Since the hundredth parts of a m illilitre are marked approximately, it can he accepted that the maximum measurement error is not less than ±0.02 ml. The error due to the remaining residue is also ±0.02 ml. Therefore, the overall error can be as much as 0.04 ml*. With the total expenditure of 20 ml of the titrating solution, this will come to 0.2% of the relative errors. It follows that, taking 1 g for analysis, the weighing can he performed with an accuracy of up to 1 mg. This gives a relative error of ±0.5 mg, or 0.05 %. If less than 20 ml of the titrating solution are used for titration, less accuracy is needed in taking a weighed portion. On the other hand, the weighing of a starting substance for esta­ blishing the litre must be performed with an accuracy of up to unity in the fourth decimal, since in this case a portion weighing only about 0.2 g is taken and about 40 ml of the titrating solution are used for titration. If one wishes to increase the accuracy of the volumetric-analytical methods, one must use gravimetric burettes instead of ordinary ones,** which completely precludes errors due to inaccurate measurement, remaining residue and a difference in temperature. The weighing of a sample now becomes a less accurate operation, and it should bo performed with a relative error which is determined by the accuracy required in the final result (±0.01% and less). The foregoing should not lead to the conclusion that the weighed portion can always be taken with an accuracy of ± 1 mg or loss. On the contrary, there are some analytical operations when the entire accuracy of an analytical balance must be used, and when even the accuracy of a microbalance is not high enough. Here are two examples. 4. Red electrolytic copper must contain 99.95% of Cu. The analy­ tical determination of Cu in this case is made by electrolysis. What accuracy must the weighing be made with? The error in the final result, expressed in per cent, must not be more than ±0.004% . It is apparently necessary to have no lesser accuracy in weighing a test of red copper as in weighing a platinum electrode before and after Cu is deposited on it. If one gram of a tost is taken for an analysis, then, with the maximum accuracy of the weighing on an analytical balance being ± 0 .2 mg, the relative error will be ±0.02% , which is far more than is permissible. Therefore, in the given case, it is necessary to use a balance th at is more accurate than the ordinary analytical one, or (as is usually done) to take not less than 5 g of the substance being analysed. 5. Suppose that for determining Zn in a copper-zinc alloy contain­ ing about 20% of Zn, a portion weighing 0.02 g is taken, whether owing to the small amount of shavings which an analyst has or with due regard to some advantages in the techniques of working with small amounts of a substance. The analysis is concluded by weighing ♦ See I. M. Koltgof and E. B. Sendel, Kolichestvennyi analiz (Quantitative

Analysis), Moscow, 1948, p. 459.

♦♦S ee, for instance, I. M. Koltgof and E. B. Sendel IColic/iistvennyi analiz (Quantitative Analysis ), Moscow, 1948, p. 561; I. M. Koltgof and V. A. Stenger, Ob'emnyi analiz (Volumetric Analysts), Voi. II, Moscow, 195 2, p. 25.

15 the precipitate in the form of Zn2P207. What accuracy must the weigning be made with? The result of the analysis must be expressed with an accuracy of up to a hundredth part of a per cent (for instance, 19.84%), i.e., with a permissible error of ±0.01% of the absolute errors; since the Zn content is 20%, this will come to ±0.05% of the relative errors. The same accuracy must be obtained when weighing the portion of shavings and the calcined precipitate Zn2P207. When a portion weighs 20 mg, the value ±0.05% comes to ±0.01 mg; the same per­ centage of the mass of the calcined precipitate ( —8 mg) is still less, being about ±0.004 mg. A microchemical balance gives an error of about ±0.01 mg. It follows that, in the given case, the weighing performed even with a microchemical balance does not ensure the required accuracy.

A

1I

Table 1 Atomic Weights of the Elements The atomic weights of various elements are determined with different accuracy which is expressed by a different number of figures after the decimal point. When the number expressing atomic weight ends with one or soveral zeroes, the latter are significant digits showing the accuracy with which the atomic weight of the corresponding ele­ ment is determined (see rule 1, p. 11). The results of chemical analyses must not be expressed with a preci­ sion greater than that of the atomic weight. This limitation must be especially reckoned with when determining some platinum and rare-earth elements, and also rhenium. The table contains relative atomic weights published by the Com­ mission on Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) in 1965. ,, The Commission adopted a resolution whereby the old oxygen chemical unit” of atomic weights (1/16 of the average atomic weight of the natural isotopic mixture of oxygen atoms) is replaced by the “carbon physical unit” (1/12 of the atomic mass of the carbon isotOPFor ali the elements, besides those given below, the number expres­ sing the atomic weight is given with an error not exceeding ±0.5 in the last digit after the decimal point. The deviations of the atomic weight values for the given six elements are as follows: boron ± 0 % 3 hy lo g en ±().00001; oxygen ±0.0001; silicon ±0.001; sulphur ±0.003; carbon ±0.00005. These deviations are due to variations in the natural isotopic composition of the elements. Owing to the experimental inaccuracies in the determination of the atomic weights of the six elements listed below, their values deviate within the following limits: bromine ±0.001; iron ±0.003; copper ± 0 001" silver ±0.001; chlorine ±0.001; chromium _ ±0.001. T he’atomic weights of radioactive elements are given only for thorium and uranium; for other radioactive elements, the mass number of the isotope with the longest half-life is given in square brackets. Symbol

Atomic number

Atomic weight, a

log a

Actinium Silver Aluminium Americium Argon

Ac Ag A1 Am Ar

89 47 13 95 18

[227J 107.868 26.9815 [243] 39.948

35 603 03 289 43 106 38 561 60 150

Arsenic Astatine Gold Boron Barium

As At Au B Ba

33 85 79 5 56

74.9216 [210] 196.967 10.811 137.34

87 461 32 222 29 440 03 387 13 780

Element

2—1845

18 Table 1 (continued) Symbol

Atomic number

weight, a

Ion u

Beryllium Bismuth Berkelium Bromine Carbon

Be Bi Bk Br C

4 83 97 35 6

9.0122 208.980 [247] 79.904 12.01115

95 483 32 010 39 620 90 257 07 958

Calcium Cadmium Cerium Californium Chlorine

Ca Cd Ce Cf Cl

20 48 58 98 17

40.08 112.40 140.12 [252] 35.453

GO 293 05 077 14 650 41 040 54 965

Curium Cobalt Chromium Caesium Copper

Cm Co Cr Cs Cu

96 27 24 55 29

[247] 58.9332 51.996 132.905 63.546

39 270 77 036 71 597 12 354 80 309

Dysprosium Erbium Einsteinium Europium Fluorine

Dy Er Es Eu F

66 68 99 63 9

162.50 167.26 [254] 151.96 18.9984

21 085 22 340 40 483 18 173 27 872

Iron Fermium Francium Gallium Gadolinium

Fe Fm Fr Ga Gd

26 100 87 31 64

55.847 [257] [223] 69.72 157.25

74 700 40 993 34 830 84 336 19 659

Germanium Hydrogen Helium Hafnium Mercury

Ge H He Ilf Hg

32 1 2 72 80

72.59 1.00797 4.0026 178.49 200.59

86 088 00 345 60 235 25 162 30 231

Holmium lodino Indium Iridium Potassium

Ho I In Ir K

67 53 49 77 19

164.930 126.9044 114.82 192.2 39.102

21 730 10 348 06 002 28 375 59 220

Krypton Kurchatovium

Kr Ku

36 104

83.80 [264]

92 324 42 160

Element

Atomic

Titbit / (nut i in uni) Symbol

Atomb’ numbe r

Atomir weight, n

Ing a

Lanthanum Lithium Lawrcncium Lutclium

La Li Lr Lu

57 3 105 71

138.91 6.939 [256] 174.97

14 273 S4 130 40 S24 24 297

Mendelevium Magnesium Manganese Molybdenum N itrogen

M(1 Mil Mo N

101 12 25 42 7

1257] 24.305 54.9380 95.94 14.0067

40 993 38 570 73 987 98 200 14 634

Sod i uni N iobium Neodymium Neon Nickel

Na Nb Nil Ne Ni

11 41 60 10 2S

22.9898 92.906 144.24 20.179 58.71

36 154 96 804 15 909 30 490 76 871

Nobclium Neptunium Oxygen Osmium Phosphorus

No Np 0 Os P

102 93 8 76 15

[255] [237] 15.9994 190.2 30.9738

40 654 37 475 20 410 27 921 49 099

Protactinium Lead Palladium Promethium Polonium

Pa Pb Pd Pm Po

91 82 46 61 84

1231] 207.19 106.4 1145] [210]

36 361 31 637 02 694 16 137 32 222

Praseodymium Platinum Plutonium Radium Hu bidium

Pr Pt Pu Ra Rb

59 78 94 88 37

140.907 195.09 [244] [226] 85.47

14 893 29 024 38 739 35 411 93 181

Rhenium Rhodium Radon Ruthenium Sulphur

Re Rli Rn Ru S

75 45 86 44 16

186.2 102.905 [222] 101.07 32.064

26 998 01 244 34 635 00 462 50 602

Antimony Scandium

Sb Sc

51 21

121.75 44.956

08 547 65 279

KlriMfllt

2*

20 Table 1 (continued) Symbol

Atomic number

Atomic weight, a

log a

Selenium Silicon Samarium

Se Si Sm

34 14 62

78.96 28.086 150.35

89 741 44 849 17 711

Tin Strontium Tantalum Terbium Technetium

Sn Sr Ta Tb Tc

50 38 73 65 43

118.69 87.62 180.948 158.924 [99]

07 441 94 260 25 755 20 119 99 564

Tellurium Thorium Titanium Thallium Thulium

Te Th Ti T1 Tm

52 90 22 81 69

127.60 232.038 47.90 204.37 168.934

10 585 36 556 68 034 31 042 22 772

Uranium Vanadium Tungsten Xenon Yttrium

U V W Xe Y

92 23 74 54 39

238.03 50.942 183.85 131.30 88.905

37 663 70 708 26 446 11 826 94 893

Ytterbium Zinc Zirconium

Yb Zn Zr

70 30 40

173.04 65.37 91.22

23 815 81 538 96 009

Element

Table 2 R ad io activ e E lem ents

Element

Ato­ Mass number Sym­ mic of the lon­ bol num­ gest living \sntope ber

Act inium Americium Astatine

Ac Am At

80 05 85

227 243 210

Bcrkelium Californium Curium Einsteinium Fermium

Bk Cf Cm Es Fm

97 98 96 99 too

247 252 247 254 257

Francium Lawrencium Men delev him

Fr Lr Md

87 103 101

223 256 257

Neptunium Nobelium Plutonium Polonium Promethium Protactinium Radium Radon Technetium Thorium Uranium

Np No Pu Po Pm Pa Ra Rn Tc Th U

93 102 94 84 61 91 88 86 43 90 92

237 255 244 210 145 231 226 222 99 232 238

Half-life*

Decay mode

22 y a , P~ 7 .8 X 103 v a 8.3 h a . Electron capture 1.4 X 103 y a a 360 y 1.6 X 107 y a 2.7 X 10= d a Electron 3d capture, a 22 min a , pa 8s 1.5 h Electron capture 2.1 X 10® y a a ~8 s 3.8 X 105 y a a 138.4 d 18 y P~ 3.2 x 104 y a a 1,622 y a 3.83 d 2.1 x 10s y P“ 1.4 x 1010 y a 4.5 x 10® y a

* s, second; min, minute; h, hour; d, day; y, year.

22

Table 3 Ion Radii The values of ion radii are given in angstroms (A) with a coordina­ tion number of 6. When the coordination number is 4, the correction comes to —6%, with the coordination number of 8, it is -(-3%, and with the coordination number of 12, it comes to + 12%. Size of radius, A, according to Substance

Ac Ag A1 Am As

Au B BFj Ba Be Bi Br C CNCa Cd Ce Cl CIO* Co Cr

Ionic charge

+3 + 1 +3 +4 +3 +5 +3 -3 +4 +3 +1 +3 —1 +2 +2 +5 +3 -3 +7 +5 —1 +4 -4 —1 +2 +2 +4 +3 +7 +5 —1 -1 +3 +2 +6

Goldschmidt

Pauling

1.13 0.57 — —

1.26 0.50 — — 0.47 — 2.22 —

—

0.69 — — — — —

— 1.43 0.34 — —

_

— —

1.96 0.2 — _ 1.06 1.03 1.02 1.18 — —

1.81 — 0.64 0.82 0.35

—

1.37 0,20 — 1.35 0.31 0.74 — — 0.39 — 1.95 0.15 2.60 — 0.99 0.97 1.01 — 0.26 —

1.81 _ — 0.72 —

Belov and Boky

other sources

l.n 1.13 0.57 0.85 1.00 0.47 0.69 1.91

1.19 — — — 0.99 — 0.58 — 0.89 0.90

—

0.85 1.37 0.21 — 1.38 0.34 0.74 1.20 2.13 0.39 1.96 0.20 2.60 — 1.04 0.99 0.88 1.02 0.26 — 1.81 —

0.64 0.78 0.35

—

— 2.28 — — — 1.16 — — 0.47 — — — 1.92 — 0.92 0.93; 0.87 1.00; 1.02 — 0.34 — 2.36 0.72 0.78; 0.80 —

23 Table 3 {continued) Size of radius, A , according to Substance

CrO?" Cs Cu Dy Er Eu F Fe Ga Gd Ge H Hf Hg Ho I

In Ir K

La

Li Lu Mg Mn

Mo

Ionic charge

+3 +2 -2 + 1 +2 i \1 ~i“ -1-3 +3 +3 +2 +7 —1 +3 +2 +3 +3 +4 +2 —4 -1 +4 +2 +3 +7 +5 +1 —1 +3 + 1 +4 +3 +2 +1 +4 +3 + 1 +3 +2 +7 +4 +3 +2 +6 -1-4

Goldschmidt

Pauling

0.83 — 1.05 0.70

_ _

1.07 1.04 1.13 — — 1.33 0.67 0.83 0.62 1.11 0.44 — — 1.54 — 1.12 1.05 — 0.94 — 2.20 0.92 — 0.66 — — 1.33 — 1.22 0.78 0.99 0.78 — 0.52 0.70 0.91 — 0.68

1.69 _ 0.96 _ _ _ _ 0.07 1.36 _ 0.75 0.62 0.53 _ 2.72 2.08 _ 1.10 0.50 _ _ 2.16 0.81 _ 0.64 _ _ 1.33 _ 1.15 0.60 _ 0.65 0.46 0.50 — 0.80 0.62 0.66

Belov and Boky

other sources

0.64 0.83 — 1.65 0.80 0.98 0.88 0.85 0.97 — 0.07 1.33 0.67 0.80 0.62 0.94 0.44 0.65

0.62 — 3.00 — 0.69; 0.82 0.95 0.91 0.87 0.96 1.09; 1.24

—

1.36 0.82 1.12 0.86 0.50 — — 2.20 0.92 1.30 0.65 — — 1.33 0.90 1.04 0.68 0.80 0.74 0.46 0.52 0.70 0.91 0.65 0.68

— —

0.73 0.75 —

0.94 —

0.98; 0.73 — —

0.86 1.05 0.89 —

0.98 1.30 2.19 —

—

0.75; 0.68 0.81 0.89 — — — — 0.84 — — — 0.67 — — —

24 Table 3 (continued) Size of radius, A, according to

Substance

Mo02N NHJ NOj Na Nb Nd Ni Np

0 OIIOHJ Os P POJ Pa Pb Pd Pm Pr Pt

Pu Ra Rb

Ionic charge

-2 +5 -1-3 —3 + 1 —1 +1 +5 +4 +3 +3 +2 +6 +5 +4 +3 +6 —2 —1 +1 +4 +3 +2 +5 +3 —0q -3 +4 +3 +4 +2 +4 +2 +3 +4 +3 +4 +2 +6 +5 +4 +3 +2 +1

Goldschmidt

Pauling

Belov and Boky

0.15

0.11

0.15

—

1.71 1.43 —

0.98 0.69 0.69 1.15 0.35 0.78 — — —

— — 1.32 — —

0.67 —

— 0.35 — — — —

0.84 1.32

—

—

—

—

0.95 0.70 0.67 —

0.98 0.66 0.67 0.99

0.69 _ _

0.74

___ ____

0.09 1.40 _ _ 0.65 _ _ 0.34

—

1.00 1.16 — — — — — —

1.52 1.49

— —

0.88 1.02 0.09 1.36 ___ —

0.65 ___ —

0.35 —

2.12 _ _ _ 0.84 1.21

—

—

—

1.48

1.86 ___

0.91 1.06 0.76 1.26 0.64

____

____

_

0.98

0.92 _ .

1.00 0.64

—

____

____

_

____

____ ____ — —

1.48

____

0.86 1.02 1.44 1.49

other sources 3.45 0.13 0.16 1.30 1.59 1.89; 2.57 — —

0.74 0.99 0.68; 0.79 0.82 0.88 0.92 1.01 —

1.45 1.53; 1.33 1.35 0.75 0.81 0.89 —

0.44 —

3.00 0.96 1.05 —

1.17 0.73; 0.65 0.72; 0.88 0.98 0.92 1.00 0.76 0.90; 0.87 0.81 0.87 0.90 1.00 —

—

25 Table 3 (continued) Size of radius, A, according to Substance

Re Rh Ru S SIl-

so * -

HSOj Sb Sc Se Si SiOJSm Sn

Ionic charge

+7 +6

+4

___

_

___

___

___

0.34

±i

1.74

-1 —2 —1 +5 +3 —3 +3 +6 +4 —2

ti •-4 +3 +2 -m

±t +2 +5 +3 +6

Th

+4 +3

Ti

+i

T1

+2 +2 +3 +1 +3

Pauling

____

+4 +3 +4 +3 +2 +6

Sr Ta Tb Te

Tm

Goldschmidt

_

0.65

___

0.63 ___ ___

0.29 ___

0.90 0.83 1 .91 0.39

1.84 _ _ _ 0.62 —

2.45 0.81 _ _ 1.98 0.41 2.71 _

1.13

___

0.74

0.71 —

1.27

2.94 1.13 ___

1.09 0.89 2.11 1.10

—

0.56 0.81 2.21 1.02 —

0.64 0.69 0.80 1.05 1.49 1.04

0.68 — —

0.95 1.44 —

Belov and Boky

other sources

0.52 0.72 0.65 0.75 0.62

0.56 0.55 0.71 0.62 0.62 0.71 0.74 0.85

— —

0.30 —

1.86 ___ ___ —

0.62 0.90 2.08 0.83 0.35 0.69 1.93 0.39 — ___

0.97 _ 0.67 1.02 —

1.20 0.66 0.89 0.56 0.89 2.22 0.95 1.08 0.64 0.69 0.78 1.05 1.36 0.85

—

0.37 1.90 2.00 2.95 2.06 — — — — 0.42 0.56 1.91 — —

2.90 0.97 1.11 — — —

1.10 0.73 0.92 0.61 — —

0.99 1.08 — —

0.76 — —

0.86

20 Table 3 (continued) Size of radius. A, according to Substance

u

V

w Y Yb Zn Zr

Ionic charge

+ 6 +5 +4 +3 +5 +4 +3 +2 +6 +4 +3 +3 +2 +4

Goldschmidt

—

1.05 —

0.4 0.61 0.65 0.72 —

0.68 1.06 1.00 0.83 0.87

Pauling

—

0.97 —

0.59 0.59 — — —

0.66 0.93 —

0.74 0.80

Belov and Boky

—

0.95 1.04 —

0.61 0.67 0.72 0.65 0.68 0.97 0.81 0.83 0.82

other sources

0.83 0.87 0.93; 0.89 1.03 0.59 0.64 — — — — —

0.85 0.70 —

27

Table 4 Ionization Potentials of Atoms and Ions The ionization potential is the minimum voltage of the electric field needed for tearing away one electron from an atom or ion. The table gives the potentials of the ionization of atoms and ions, i.e., the potentials required for separating one electron from a neutral unexcited atom (X — e X+) and the potentials required for tearing away one electron from a single-charge (positive) unexcited ion (X+ — e Xa+), from a two-charge unexcited ion (Xa+ — e -► X3*) and so forth. Insufficiently reliable data are given in parentheses. + X t 1 X

C4

Element

Ac Ag A1 Ar As Au B Ba Be Bi Br C Ca Cd Ce Cl Co Cr Cs Cu Dy Eu P Pe Ga Gd Ge H lie

Si t 0 1 X 6.89 7.57 5.98 15.76 9.81 9.22 8.30 5.81 9.32 7.29 11.84 11.26 6.11 8.99 6.91 13.01 7.86 6.76 3.89 7.72 6.82 5.67 17.42 7.90 6.00 6.16 7.88 13.60 24.58

i vt +I to *

* t

6.10 28.44 40.90 28.3 30.5 37.92 37 153.9 25.6 35.9 47.86 51.21 44.5 19.5 39.9 33.5 31 34.6 36.83

(52) 119.96 59.79 50.1 (44) 259.30 (49) 217.7 45.3 47.3 64.48 67.3 (55) 36.7 53.3 (53) (51) (46) (59)

70) 153.8 75.0 62.9 (58) 340.13 (62)

(89) 190.4 91.3 127.5 (73)

56.0 59.7 392.0 84 (73) (70) 67.8 (82) 73 (62) (83)

94.4 88.6 489.8 109 (94) (85) 96.6 (109) 90.6 (74) (109)

62.65 30.64 30.70

87.23 (56) 64.2

114.2 (79) (90)

157.1 103 (118)

34.21

45.7

93.4

(123)

V

11.5 21.48 18.82 27.62 18.7 20.5 25.15 10.00 18.21 19.3 21.6 24.38 11.87 16.90 12.3 23.80 17.05 16.49 25.1 20.29

i

* t

r

t +I

(80)

—

11.24 34.98 16.18 20.51 12 15.93 —

54.40

Table 4 (continued)

Klemont

Hf Hg I In K Kr La Li Lu Mg Mn Mo N Na Nb Nd No Ni 0 Os P Pb Pd Po Pr Pt Ra Rb Re Rh Rn Ru S Sb Sc Se Si Sm Sn Sr Ta 'll)

+ * t % » 1 5.5 10.43 10.4 4 5.70 4.34 14.00 5.01 5.39 6.15 7.64 7.43 7.13 14.54 5.14 6.88 6.31 21.56 7.63 13.61 8.7 10.55 7.42 8.33 8.2 5.76 8.96 5.28 4.18 7.87 7.46 10.75 7.36 10.36 8.64 6.56 9.75 8.15 5.6 7.33 5.69 7.7 6.74

*+1 t +1 14.9 18.75 19.0 18.80 31.8 24.50 11.43 75.02 14.7 15.03 15.64 15.72 29.60 47.29 13.90 _ 41.07 18.15 35.15 17 19.65 15.03 19.42 19.4 _ 18.54 10.14 27.56 10.0 15.92 21.4 16.60 23.4 16.7 12.89 21.5 16.34 11.2 14.6 11.03 16.2 ■-

n+ t 1 e+» X (21) 34.2 33 28.0 45.9 30.9 19.17 122.4 (19) 78.2 33.09 29.0 47.43 71.05 28.1 —

03.5 30.16 54.93 25 30.16 31.93 (33) 27.3

T+ tI V +31 C (31) (46) (42) 58 01.1 52.5 (52, —

109.3 (33) 40.4 77.45 98.8S 38.3 —

97.2 50 77.39 40 51.35 39.0 (49) (38)

—

—

(29) (34) 40 (20) 32.8 29.4 30.3 34.8 24.8 24.75 32.0 33.40

(41) (46) 52.6 (38) (40) (44) (47) 47.3 44.1 73.9 42.9 45.1

—

30.7 43.0 (22)

—

40.4 57.1 (33,

V I + > (6l) 71 (77) 82.6 64.7 (66) — — 141.2 (76) 61.2 97.86 138.6 50 — 126.4 79 113.9 54 65.01 69.7 (66) (61) — (55) (59) 71.0 (51) (67) (55) (63) 72.5 63.8 91.8 68.3 166.7 — 91 71.6 (45, -

+ to t; V 1 +O l _ (77) 83 (98) 99.4 78.5 (80)

-186.8 100 67 552 172.4 110.4 — 157.9 113 138.1 68 220.4 84 (90) (73) — (75) (76) 84.4 (65) (85) (67) (81) 88.0 119 111 82.1 205.1 — (103) 90.8 —

29

Element

Tc Te Th Ti T1 V W Xe Y Yb Zn Zr

+ X t (I 1 X 7.23 9.01 6.83 6.11 6.74 7.98 12.13 6.38 6.2 9.39 6.84

+ X t tl +1 X

0+1 * t ti } X

t +1 n X

14.87 18.8 11.5 13.57 20.42 14.2 17.7 21.2 12.23 12.10 17.96 12.92

31.9 31 20.0 28.14 29.8 29.7 (24) 32.1 20.5

(43) 38 28.7 43.24 50 48.0 (35) (45 61.8

e»

—

39.70 24.8

+

**

t>

—

(62) 33.97

Table 4 (continued) + + X X t t ti 1 + +1 X X lO

CD

lO

(59) 66 (65) 99.8 (64) 65.2 (48) (57) 77.0 —

(86) 82.3

(76) 83 (80) 119 (81) 128.9 (61) 89 93.0 —

(114) 99.4

w c: o •

C2 *o CO

< + r?

^3 IDvr

ou

_

n :*

O

m x I c

~ vr I

« CO