1534 MAGNETIC STUDY OF SOME BORON COMPOUNDS The

1534

MATA ERASAD, C. R. KANEKAR, AND L. S. KAMAT

MAGNETIC STUDY OF SOME BORON COMPOUNDS MATA PRASAD, C. R . KANEKAK,

A N D MISS L. S. KAMAT Chemical Laboratories, The Institute of Sczence, Bombay, India

Received October 16, 1960

The atomic susceptibility of boron has been reported by Pascal (19). The susceptibilities of the element boron and of boron hydrides have also been measured (cf. Klemm (13)). However, little work has been done on the susceptibilities of boron compounds of various types. The chemistry of boron is interesting, especially from the point of view of the constitution of polyborates. The present investigatioil deals with the study of the susceptibilities of a large number of boron compounds, including several polyborates. I . EXPERIMENTAL

The borax and the potassium borofluoride used in this investigation were of British Drug Houses A. R. quality and the orthoboric acid was of May and Baker's A. R. quality. Other substances were prepared in the laboratory; details of the methods are given below because of difficulties in the preparation of many of the substances in the pure state. Preparation of boron compounds 1, Metaboric acid (cf. G m e h (6)): Metaboric acid was obtained by dehydrating orthoboric acid at 100°C. to constant weight. The loss in weight corresponded to the theoretical value within an error of 0.5 per cent. 8. Boric oxide (cf. Gmelin (6) and Lorenz (14)): Orthoboric acid, twice recrystallized from hot water, was melted in a platinum crucible and heated over the oxygen flame until the mass flowed freely and was absolutely free from air bubbles. On cooling, the liquid set to a hard glass. The crucible was then immediately placed in a desiccator over phosphorus pentoxide overnight whereupon, on slight squeezing, the glass separated in a solid block which was pulverized as soon as possible. The loss in weight corresponded to the theoretical within an error of 0.46 per cent. 3. Potassium tetraborate octohydrate (cf. Menzel (16)): 10 g. of potassium hydroxide and 22 g. of recrystallized orthoboric acid in a ratio slightly greater than 1:2 were dissolved in the minimum amount of warm water. Crystals were obtained on keeping the solution in a desiccitor for 3 or more weeks. Contrary to Menzel, the yield was poor. Boron content: found, 11.43 per cent; theory, 11.46 per cent. 4. Sodium pentaborate pentahydrate (cf. Rosenheim and Leyser (26)) : One mole of sodium hydroxide and 5 moles of orthoboric acid were dissolved in water. The first crop of crystals obtained on evaporating the solution in I ~ U C U O contained a little boric acid, and the last crop a little borax; hence only the middle crop was collected. The crystals were dried very carefully, as they rapidly lose water at 8OoC. Boron content: found, 18.05 per cent; theory, 18.33 per cent. 6. Potassium pentaborate tetrahydrate (Rosenheim and Leyser ( 2 6 ) ): This salt was obtained on boiling a solution containing potassium hydroxide and

MAGNETIC SUSCEPTIBILITIES OF SOME BORON COMPOUNDS

1535

orthoboric acid in the proportion of 1:4. The product was twice recrystallized from water. Boron content: found, 18.35 per cent; theory, 18.45 per cent. 6. Calcium decaborate enneahydrate (cf. Rose (25) and Mellor (15)). Concentrated solutions containing equimolar quantities of borax and calcium chloride were cooled to 8°C. and then mixed with continuous vigorous stirring. The precipitate obtained was filtered off and thoroughly washed to remove the excess of either reagent. I t was then dried first in a desiccator and finally in an air oven. Boron content: found, 15.97 per cent; theory, 15.94 per cent. 7. Strontium and baraum decaborates: The same procedure as described above was followed. Boron content for strontium salt: found, 13.68 per cent; theory, 13.77 per cent. Boron content for barium salt: found, 11.76 per cent; theory, 11.79 per cent. 8. Sodium metaborate dihydrate (cf. Benedikt (1)) : Benedikt obtained crystals of SaBOn. 4H10 by concentrating a boiling solution of equimolar proportions of sodium hydroxide and borax to a thin syrup and crystallizing it over concentrated sulfuric acid. The authors failed to repeat this experiment. However, they found that crystals of the dihydrate were formed when the above mixture was allowed to stand for 2 or 3 weeks in a desiccator. Boron content: found, 10.61 per cent; theory, 10.62 per cent. 9. Sodium metaborate (anhydrous) : This salt was prepared by carefully heating the dihydrate until the loss in weight corresponded to 2 moles of water within an error of 0.2 per cent. 10. Sodium boroformate dihydrate: A concentrated dolution of 1 mole of sodium formate and 1 mole of orthoboric acid was gently evaporated at about 50°C., and the crystals which separated on cooling were sucked off from the mother liquor and recrystallized. The purified crystals were then dried very gently in an air oven a t 45-50'C. Boron content: found, 6.56 per cent; theory, 6.52 per cent. 11. Potassium boroformate: The dihydrate (see paragraph 10) was dehydrated at 105°C. until the loss in weight corresponded to 3 moles of water within an error of 0.3 per cent. 12. Potassium borodicatechol (cf. Rosenheim and Vermehren (27)) : Two moles of catechol were added to a solution containing 1 mole of orthoboric acid and 0.5 mole of potassium carbonate with plenty of water, and the mixture was boiled until all of the catechol ivent into solution. The solution after filtration was concentrated slightly on a water bath and allowed to stand for 2-3 hr. The crystals thus obtained vere filtered off, washed thoroughly, and dried. Boron content: found, 4.10 per cent; theory, 4.13 per cent. 13. A m m o n i u m borodicatechol: The procedure followed was the same as in paragraph 12, the solution consisting of 1 mole of orthoboric acid and 0.5 mole of ammonium carbonate. Boron content: found, 4.25 per cent; theory, 4.49 per cent. 14. Boron pyroacetate: A mixture of orthoboric acid and acetic anhydride (extra pure) in the ratio 1:3 by weight was gently heated on a water bath. All apparatus used was absolutely dry. As the temperature reached 60°C. a violent reaction took place, whereupon the liquid reached its boiling point and the boric acid went into solution. On allowing the solution to cool in a desiccator the mixed

1536

MATA PRASAD, C. R. KANEKAR, AND L. 8. KAMAT

anhydride crystallized out. The substance was purified by recrystallization from warm purified glacial acetic acid, washed with dry ether, and dried in a desiccator. The above method of preparation was first used by Pictet and Geleznoff (21), who assigned the formula (CH3C00)3Bto the substance and reported its melting point as 121°C. Dimroth et al. (4) used the same method and obtained a substance of the formula [(CH&OO)~B]~O and having a melting point of 150TABLE 1 dlagnetic susceptibilities of some boron compounds I O W L A

XY‘

Orthoboric acid

0.578

35.72

Metaboric acid Boric oxide Sodium tetraborate (anhydrous)

0.517

0.556

22.65 38.73

38.30 hleyer (18)

0.423

85.10

80.5 Prasad,

0.390

80.07

0.394 0.448

87.10 304.1 213.4 312.4 247.6 327.8 275.96

Sodium pentaborate (anhydrous), . . . I’ot.assium pentaborate (anhydrous). . Calcium decaborate Strontium decabornte

0.398

Barium decabornte

0.358

Potassium borofluoride . . . . . . . . . . . . . . . Sodium metaborate (anhydrous). . . . . . . Sodium boroformate hydrate . . . . . . . . . . . Sodium boroformate (anhydrous) . . . . . . . Potassium borodicatechol. . . . . . . . . . . . . Ammonium borodicatechol. . . . . . . . . . . . . Boron pyroacetate.. .

0.432

54.42

0.417

31.42

0.536

88.88

0.419

46.86

0.523

139.2

0.537 0.532

131.6 145.6

32.16 Meslin (17) 34.8 Kido (12)

Dharmatti, Kanekar, and nirntlar (23)

D a t a obtained by the authors.

152°C. The melting point of the substance prepared by the authors was 152°C. Analysis showed that the compound was the same as that obtained by Dimroth. Boron content: found, 7.84 per cent; theory, 7.91 per cent. II. REBULTB

The magnetic susceptibilities of the compoundR were measured by using a modified form of Gouy’s balance (cf. Prssad, Dharmatti, and Gokhale (22)).


1537

The results obtained are given in table 1, in which x. and xH represent the specific and molar susceptibilities of the compounds, respectively. The experimental values reported by previous workers are given in the last column. All the values C.G.S. units. of susceptibilities are expressed in terms of - 1 X The calcium, strontium, and barium decaborates are associated with 9, 7, and 6 molecules of water of crystallization, respectively. These salts have the same anion: namely, 2(B,09.H10)---. Assuming that the contribution of the susceptibility due to molecules of water not attached to the decaborate anion is normal (12.96 per mole), the molar susceptibilities of the diKydrates have been deduced from the observed values of x u of each hydrate, and are given below these values in table 1. TABLE 2 Magnetic susceptibilities of anions containing boron

BO; . . . . . BF; . . . . . . . B,0; - . . . . . . BaO; . . . . . . .

/I

I

ION

. . . . . . . . ./ . . . . . . . . . . . . ............. . . . . . . . . . .. . . ,

24.20 39.41 71.15 72.59

ION

I

[HCOOB(OH)a]-... . . . . . . . . . . . . [HCOOB(=O)OH]-. . . . . . . . . . . . [(C6H,O1)?B]-. . . . . . . . . . . . . . . . . [BipOia.2H20]---. . . . . . . . . . . . .

XION

55.98 39.89 123.11 180.10

111. DISCUSSION OF RESULTS

It will be observed from table 1 that the molar susceptibilities observed by the authors agree well with those reported by previous workers. 1. Susceptibilities of anions containing boron The magnetic susceptibilities of various anions containing boron have been calculated by subtracting the susceptibilities of the cations from the molar susceptibilities of the compounds studied in this investigation and are given in table 2. Since the literature provides a number of varying values for the susceptibilities of sodium and potassium ions, the authors have subtracted all the known values given below of the susceptibilities of these ions reported in the literature (cf. Prasad and coworkers (24)). XNa'

9.2 6.5 10.4 6.8 7.6 4.0 5.2 5.2 6.1 8.2 7.6 6.9

XK.

________ 18.2 14.5 16.9 14.9 13.6 11.0 14.5 13.5 14.6 16.5 16.0 15.6

SOUlCl

International Critical Tables Joos (11) Ikenmeyer (10) Trew (29) Kido (12) Sugden (28) Pauling (20) Brindley (2) Brindley and Hoare (3) Hocart (9) Pascal (19) Flordal and Frivold (5)

1538

MATA PRASAD, C. R. KANEKAR, AND L. 5. KAMAT

The values of xCa++, xSr4+, and xBa.+used are the average values ohhined by Prasad and coworkers (namely, 10.65,22.61,and 32.31, respectively), since they represent the most probable values for these cations in combination with any anion. 2. Relationship of the polyborate ions The chemistry of polyborates has been a subject of much discussion, and various attempts have been made-notably by Hermans (8), Menzel (16), Wiberg (31), and Hahn (7)-to devise their most suitable constitutions. It is

O'

40 i o I20 160 200 NUMBER OF ELECTRONS IN ANDN

O

'

i

2 3 4 B203 CONTENT

5

6

FIG.1 FIG.2 FIG.1. Plot of magnetic susceptihilities of the metahorate, tetrahorate, and pentahorate , , SarB4O7, ions against the total number of electrons in the anions. Curve I : (1) N I I . ~ R ~ O(2) (3) N a ~ B I 0 O Curve 1 ~ . 11: (1) B20,- -, (2) B40,--, (3)BloO16-FIG.2. Plot of molar Susceptibilities of sodium polyhorates against the B& content: (1) SalBtO,, (2) NarB407, (3) Sa&oOls. noteworthy that the fundamental principles on which these workers have based their structures are widely different. In the present paper, no attempt has been made to utilize the magnetic data for the elucidation of the constitution of polyborates or t o test the correctness of the several constitutions proposed by various workers. This will form the subject of a later communication. The results obtained in this investigation have only been utilized to discuss the relationship of some of the polyborate ions. No definite relation has been observed between the susceptibilities of the anions containing boron and the total number of electrons in the ions. However, when the susceptibilities of the metaborate, tetraborate, and pentaborate ions, expressed in the dimeric fashion, are plotted against the total number of electrons

1539


(N') in them, the plotted points are found to be on a straight line (curve 11, figure 1). This linear relation suggests that the constitutions of the tetraborate and pentaborate ions are related to that of the metaborate ion. This observation is in conformity with the contention of Hahn that the constitutions of the polyborates must be expressed in such a manner that they may bring out their relationship to the metaborate ion, and the change of the polyborates to metaborate taking place on solution may be expressed as easily as the change of dichromate to chromate. Since it is possible t o represent the constitution of polyborates as consisting of a number of B203 molecules, Wiberg considers that all polyborates contain B203molecules as a fundamental unit. On this basis the meta-, tetra-, and pentaborate ions can be expressed as members of a series containing an increasing number of B203units as follows:

+ OB203 BIOT-- = 2(B02)- + 1Bz03 Z(Bs08)- = 2(B02)- + 4Bz03 BzO4-- = 2(B02)-

This relationship is supported by the magnetic data, since the molar susceptibilities of the sodium salts of these polyborates are a linear function of the number of B203groups in them (cf. figure 2). In order to justify this conclusion further, values of the tetraborate and pentaborate ions have been calculated by adding in requisite molar proportions the observed value of xEaOl(38.73) to the average value of xB0? (24.20); the values thus obtained are given in table 3. TABLE 3 Molar susceptibilities of the tetraborate and pentaborate ions ~~

ION

B,O; - , . . . . . . . . . . , , . . 2(BaOs)- -. . . , . . . . . . .

XIOS

XlOK

DIFFERENCE

(OBSERVED)

Ax

71.15 145.18

15.98 58.14

AxX/BzOa

16.0 14.5

It will be observed that the calculated values are higher than the observed ones. This is expected, since the addition of molecules to the metaborate ion ivould produce a depression, owing to bond format'lon. This depression in diamagnetism per mole of B203has been found to be fairly constant (last column). Further, the value of xM, in combination in polyborates, calculated from the slope of the line in figure 2, is found to be 23.8, the observed value of xBIol being 38.73. Thus the depresaion in diamagnetism caused by the binding of B2O3in these compounds is 14.9, a value which is in fair agreement with the values of Ax/Bz03 given in table 3. The considerations given above can be extended to the constitution of the dihydrated decaborn.te ion, [2(BsO9.HzO)]---, which can be expressed as being

1540

MATA PR.4SAD, C. R . K.4NEKAR, AKD L. S. KAMAT

related to either the metaborate or the orthoborate ion, as follows:

+ 4HBOz = G(B0z)- + '2(&03.HzO)

[2(BbOs.H20)]--- = G(B0z)-

(1)

or

[2(BsOs.H20)]- - - = z(BO3)- - -

+ 4HBOz + 2B203

+

+

= 2(B03)--2(BzOa.HzO) 2B203 (11) In both cases it has been assumed that metaboric acid is a hydrate of Bz03 and that the water molecules in the decaborate ion are attached to the B203 in the same manner as in HB02. Values for the susceptibility of the decaborate ion were calculated by adding in the required proportion the observed value of xHm, (22.65) to the average value of xBOf-(24.20) in case I and to the sum of the values of xBor-- (35.72), obtained from assuming Hf to be zero, and xBIos(38.73) in case 11; these values are given in table 4.

TABLE 4 Calculated values for the magnetic susceptibility of the decaborate ion

I. . , , . . . . . , . I1 , . , . . . . , .

I

+

6(BO;) ~(B~OJ.HZO) 2(B101.H20) 2(BO; - - )

+

+ 2B101

I

235.8 239.5

1 I 55.7 59.4

27.9 14.9

It will be seen that both of the calculated values are higher than either the average observed value (180.1) or the value obtained from the graph (see figure 3) (182.0) for the hydrated decaborate ion. This again may be due to the depression caused by bond formation between BO2 and metaboric acid or BO3---, or between metaboric acid and B2O3.In case 11,the difference between the calculated and the observed average values of xlonper molecule of Bz03 (Ax/B,03), given in the last column of table 4, agrees with the values of the depression estimated in B1O,- - and BsOs- ions. Considering the complexity in the assumption regarding the linkage of water in the decaborate dihydrate ion, it may be concluded that the magnetic data lend support to the view that it is more closely related to the Boa--- than to the BOZ- ion. It may be noted that the decaborate ion, like the B03--- ion, is trivalent. 3. Grap.'lical representation of molar Susceptibilities (a) Relation between x W and N

Kid0 (12) and Prasad and coworkers (24) have established a linear relation between the molar susceptibilities (x.") of salts of chemically related cations with a common anion and the number of electrons ( N ) contained in the cations. The truth of this relation ran be tested in the case of the decaborates of calcium,

1541


strontium, and barium, which contain the same hydrated anion: namely, [2(B500.HzO)---].Hence the values of x u of the dihydrates of these borates (cf. table 1) were plotted against N and the plotted points were found to be on a straight line (cf. figure 3).

fz P

x

:;v 200 20 10

I80

0

........ ...... ........ ..... .... L

L

J

.A

__.A

........

ATI IONFIG.3. Plot of molar Susceptibilities of calcium, strontium, and barium decaborate dihydrates against the number of electrons (N) contained in the cations. Curve I : xu-N for (1) calcium decaborate dihydrate, (2) strontium decaborate dihydrate, and (3) barium decaborate dihydrate. Curve 11: xlo.-N for (1) calcium ion, (2) strontium ion, and (3) barium ion. TABLE 5 Values of the maanelic susceptibilities of calcium, slronlium, and barium ions XION ( G U P U )

ION

X.4

Ca++,. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sr++. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ba++.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I ~ ( B L O ~ . H ~ O ) ] -. -. -. .. . . . . . . . . . . . . .

10.46 21.60 31.30 182.0

1 ~

XION AVERAGE (PPASAD AND COWORKERS)

xB

10.50 22.54 31.50

10.65 22.61 32.321 180.1

Prasad and coworkers have shown that in cases where the xu-N relation holds the intercept of the straight line on the xM-axisis a measure of the susceptibility of the anion, and the slope of the straight line is the contribution per electron in the cation to the molar susceptibilities of the salts of the chemically related elements. Hence this relation has been used to calculate the susceptibilities of the alkaline earth ions and of the decaborate dihydrate ion in these borates. The latter value comes out to be 182.0, a value which agrees very well with

1542

MATA PRASAD, C. R . KAKEKAR, AKD L. S. KAMhT

the observed average value (180.1) for the susceptibility of the ion. This agreement s h o w that the xM-N relation does give definitely reliable values of xanion. The values of the susceptibilities of calcium, strontium, and barium ions have been calculated in two ways: ( I ) by subtracting the value of the anion (182.0) from the observed x u of the dihydrate and ( 2 ) by multiplying the slope of the straight line by the number of electrons in the cations. These values have been designated as xA and xB, respectively, in table 5. The values of X A and X B are nearly equal; values of xB are, however, more reliable than those of x.,, since the latter contain small experimental errors which are smoothed out in drawing the graph. Both values are in excellent agreement with the average values of alkaline earth ions obtained by Prasad and colvorkers (column 4) from salts of inorganic acids. This agreement further supports the reliability of the values obtained by the graphical method. (b) Relation between x M and N’ The relation discussed in the foregoing paragraph refers to salts of chemically related cations with a common anion. Since the polyborates have been shown to be chemically related (cf. Section 111, 2), an attempt has been made to test whether a similar relation holds between the molar susceptibilities of salts of chemically related anions (borate ions) with a common cation and the number of electrons ( N ’ ) in the anion. For this purpose the values of x,,, of sodium salts of the meta-, tetra-, and pentaboric acids have been plotted against N’;the meta- and the pentaborates are generally considered univalent, but in order to bring them to a comparative basis they have been assumed to have dimeric formulae and the values obtained by doubling their x,, values have been used for plotting the graphs. The plotted points lie on a straight line (figure 1). In order to confirm whether the relation is definitely linear, the values of xu were calculated from the slope and the intercept of the line and were found to be in good agreement with the observed ones. If the considerations employed by Prasad and coworkers in the case of the X . ~ - Nrelation are applied to the linear relation between x Mand N‘,the intercept of the straight line on the xM-axis should be a measure of the susceptibility of the cation and the slope of the line should represent the contribution per electron in the anion of the salts to the susceptibilities. The susceptibilities of the sodium ion and of the borate ions found in this manner are given in table 6. For the sake of comparison the average values for the susceptibilities of sodium ion [reported by Trew (29)] and of the borate ions (table 2) are given in the last column of table 6. The values obtained from the graph for the susceptibilities of the borate ions are in all cases lower than the average values by about 16.0,and the susceptibility of the sodium ion is more than twice the value given by Trew. It will be further noticed from figure 1 that the xrN‘ straight line (I) is parallel to the straight line (11) obtained by plotting the susceptibilities of the meta-, tetra-, and pentaborate ions against N’.This fact establishes that the ionic susceptibilities of sodium ion and of borate ions are additive (Pascal’s


1543

law). Hence the average difference (15.0) between the two ordinates for the same value of N' would be twice xsa+ or the value of xNa+is 7.5, which is in fair agreement with Trew's reported value. It is clear, therefore, that the value of xNa+ obtained from the xH-N' graph is not the real value, because the intercept of the line 11 is the sum of the susceptibility of the sodium ion and of the intercept (15.0) of the line I1 on the xlon-axis.For the same reason the susceptibilities of the borate ions given in table 6 would have to be increased by 15.0. The values thus obtained are 46.68, 71.16, and 144.6, respectively, which agree with the values reported in table 2. The above discussion leads to the conclusion that even though the XTN' relation is linear, it cannot be utilized for the evaluation of the susceptibilities of ions, since the susceptibilities of such chemically related anions are not merely a function of the number of electrons in the anion but contain a constauL, TABLE 6 Magnetic susceptibilities of the sodium ion and of borate ions found f r o m the graph W g u r e l ) ION

' 11

K a+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B20;- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I

BdO; - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BloOL-, . . . . . . . . . . . . . . . . . . . . . . . . . . .........I

15 31.68 56.16 129.6

1 ~

6.8 48.4 71.15 145.18

the value of which is given by the intercept of the x r N ' line on the Xion-axis. The exact significance of such an intercept is, however, doubtful, since its existence indicates a diamagnetic contribution when the number of electrons in the anion is zero. The susceptibilities of chemically related cations deduced from their inorganic salts were found by Kid0 to be a linear function of the number of electrons in the ion, the straight line obtained in this manner passing through the origin. Prasad and coworkers also found this observation to be true. The xAvalues of alkaline earth cations deduced from the decaborates also lie on a straight line passing through the origin when they are plotted against N (cf. figure 3); this leads to the conclusion that while the susceptibilities of chemically related cations are a simple function of the number of electrons in the ion, the anions containing boron do not behave in an analogous manner. (c) X T Z Z relation Ikenmeyer (IO) has observed a linear relation between the molar susceptibilities of alkali and alkaline earth salts and the total number of electrons (XH)in the molecule. When the molar susceptibilities of all the compounds of boron studied in this investigation were plotted in this manner, a nonlinear graph (figure 4) was obtained. Considering the wide divergence in the chemical nature

1544

MATA PRASAD, C. R . KANEKAR, AND L. 8. KAMAT

of the compounds investigated, this result is not, at all surprising ana is in conformity with the observations of Prasad and coworkers. Figure 4, however, shows that the points representing the molar susceptibilities of the decaborates of calcium, strontium, and barium lie on a straight line. This leads to the conclusion that Ikenmeyer’s relation is true for salts containing a common anion and chemically related cations. In fact, Ikenmeyer obtained a linear relation only for the salts whose cations and anions are chemically related. The linear relation between x M and N observed for these decaborates (figure 3) is merely a specific case of the Ikenmeyer relation. 32s280-

I

ab

I60

240 320 400

TOTAL NUMBER OF ELECTRONS

FIG.4. Plot of molar susceptibilities of boron compounds against the total number of electrons in the molecule. 1 2 3 4 5

HBOi NaBO? Bz0r [HCOOB(=O)OH]Ka KBF,

Another interesting observation made from figure 4 is that the points corresponding to the molar susceptibilities of metaboric acid, sodium metaborate, potassium borofluoride, sodium boroformate, and fhe borodicatechols lie on a straight line. It is noteworthy that all these compounds contain one or more quadricovalent boron atoms. It therefore appears probable that the linear relation between x N and Zz also holds within permissible limits for compounds containing anions having common characteristics, even though the chemical constitution and crystal structure of these compounds may be widely different.


SUBST*NCE

HBO, H3B03

-II

PROPOPTION OF

Bat

f(B:OS )(B2O3

+ HtO) + 3HxO)

XY

XY

Ahm

WATER

(OBSEPVLD)

-AX.” _

kg:j

1545

xma

-___________ 22.65 35 72

25.84 38.80 1

-3.19 -3.08

-3.19 -1.03

6 57 10.90

The deviation per molecule of water attached to & 0 3 (AxM/n)is higher for metaboric than for orthoboric acid. This observation is analogous to that of Prasad, Dharmatti, Kanekar, and Biradar (23), who found that the deviation per molecule of water in the case of the several hydrates of the same salt is least for the hydrate containing the greatest number of molecules of water and is highest for that containing the least number. This analogy is remarkable, since in boric acids the water is attached in the form of chemical linkages. The values of xHIOcalculated from the susceptibilities of the acids by using the value of xBlo8(38.73) also support this conclusion. The molecular diamagnetic susceptibility of a polyatomic molecule without a resultant spin is represented according to Van Vleck (30) by the expression:

(1st term) n’

+n

(2nd term)

The first term is the well-known Langevin equation; the second is a paramagnetic term independent of temperature, and is brought about by the distodion of the electronic system due to interatomic forces which come into play in polyatomic molecules. Its value would vary with the different linkages in the molecule. The depression in diamagnetism observed in this, investigation can be attributed to this term only; however, its exact function is not quite clear.

1546

MATA PRASAD, C. R. KANEKAR, AND L. S. KAMAT V. SUMMARY

Magnetic susceptibilities of a number of compounds of boron have been determined on a modified form of Gouy’s balance. The data obtained have been utilized to deduce the magnetic susceptibilities of various ions containing boron. Relationships between (i) the tetra- and pentaborate ions and the metaborate ion and (ii) the trivalent hydrated decaborate ion and the trivalent orthoborate ion have been established. The molar susceptibilities ( x I ) of the decaborates of alkaline earths are a linear function of the number of electrons ( N ) in the cations; values calculated for the susceptibilities of the constituent ions from this relation are in good agreement with their average values. A similar linear relation also exists between the X M values of the meta-, tetra-, and pentaborates of sodium and N‘, the number of electrons in the anion; the peculiarity of this relation has been explained. The important deductions presented in the paper are that while the susceptibilities of chemically related cations in combination with an anion are a simple function of N , this is not true in the case of the chemically related anions, such as the meta-, tetra-, and pentaborate ions in combination with the same cation. Ikenmeyer’s relation has been found to be true for some compounds in which the anion contains exclusively a quadricovalent boron atom. Considering the boric acids to be a molar combination of B20sand H20in different proportions, the behavior of water in combination in the metaboric and orthoboric acids has also been discussed. REFERENCES (1) BENEDIKT,R.: Ber. 7, 700 (1874). (2) BRINDLEY, G. W : Phil. Mag. 11, 786 (1931). (3) BRINDLEY, G. W.,A N D HOARE,F. E . : Proc. Roy. Soc. (London) Al62, 342 (1935). (4) DIMROTH, O.,et a l . : Ann. 448, 97 (1925). (5) FLORDAL, M., A N D FRIVOLD, 0. E . : Ann. Physik [5]23, 126 (1935). (6) GMELIN,L.: Handbuch der anorganischen Chemie, Vol. 13,pp. 65 and 71. (7) HAHN,F. L.: 2. anorg. Chem. 193, 316 (1930). P. H . : Z. anorg. Chem. 142,s (1925). (8) HERMANS, (9) HOCART, R . : Compt. rend. 168,1151 (1929). (10) IKENMEYER, K . : Ann. Physik [5]1, 169 (1929). (11)Joos,G.:2. Physik 19,347 (1923);S2,835 (1925). (12) KIDO,K.: Science Repts. TBhoku Imp. Univ. 21, 869 (1932). (13) KLEMM,W.,A N D COWORKERS: 2. anorg. Chem. 226, 258-61 (1935);2. Elektrochem. 46, 346-53 (1939). (14) LORENZ, R..Ann. 247, 226 (1858). (15) MELLOR,J. W.:Comprehensive Treatise on Inorganic and Theoretical Chemistry, Vol. V, p. 91. Longmans, Green and Company, London (1924). (16) MENZEL, H.: 2. anorg. Chem. 166.75 (1927). (17) MESLIN,G.: Ann. chim. phys. 7, 145 (19oa). (18) MEYER:Ann. Physik68, 325 (1899). International Critical Tables, Vol. VI. McGraw-Hill Book Company, Inc., (19) PASCAL: New York (1929). (20) PAULINQ, L.: Proo. Roy SOC.(London) A114. 181 (1927). (21) PICTET,A,, A N D GELEZNOFF, A.: Ber. 96,2223 (1903). (22) PRASAD, M., DHARMATTI, S. S., A N D GOKHALE,S. V.: Proc. Indian Acad. Sci. 20A, 2.24 (1944).

SULFAMATES AXD METHANESULFONATES OF ZINC AND MAGNESIUM

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(23) PRASAI), AI,, DHARMATTI, s. s.,KANEKAR, c. R . , A N D BIRADAR, S . S.: J. Chem. Phys. 17, 803-18 (1949). (24) P R A S A Ibl., I , A N D CON-ORKERS: h o c . Indian Acad. Sci. MA, 307 (1942); IOA, 224 (1944); 24A, 312, 323 (1947). (26) ROSE,H . : Pogg. Ann. 86,561 (1852). (26) ROSESHEIN, A . , A S D LEYSER, F . : Z . anorg. Chem. 119, 1 (1021). h . , A S D V E R Y E H R E NH, . : Ber. 67, 1337 (1924). ( 2 i ) ROSENHEIM, (28) S C O D E N S.: , J. Chem. SOC.1932, 164. (29) T R E WV , . C. (3.:Trans. Faraday SOC.37, 488 (1911). (30) VANVLECK,J. H . : The Theory of’ Electric and Magnetic Snpceptibilities, p. 275. Oxford University Press, London and S e w York (1032). (31) WIBERG, E . : Z . anorg. Chem. 191, 43 (1930).

SOME COSDCCT.iSCES AND FREEZISG POISTS OF AQUEOUS METHASOL SOLUTIOSS OF THE SULFAMATES AND METH.iSESULFONATES OF ZISC A S D MAGNESIUM1 L. R. DAWSOS, WJI.hl. KEELT, H . L. DAVIDSOK, G . R . LEADER, H. K . ZIMMERMAS, JR.

AND

Department of Chemistry, Cniuerszly of Kentucky, Lezington, Kentucky Receiued October P4, 1950

I t appears from the literature that very little investigative work has been done on the properties of solutions of salts of sulfamic acid and of the alkane(or a1kyl)sulfonic acids. Among the physical properties which have been studied are the solubilities in water of the sulfamates of barium, calcium, and magnesium, which have been determined by King and Hooper (2), while the viscosities of these solutions, as well as that of ammonium sulfamate, have been reported by Schmelzle and Westfall (5). Regarding the alkanesulfonates, conductivities for a number of the sodium salts have been measured by Paquette, Lingafelter, and Tartar (3), and the conductances in dilute solutions have been estimated for the methane- and ethanesulfonic acids by Berthoud (1). Since all of this work was done in aqueous solutions, and since salts of this type appeared from exploratory observations to be fairly soluble in nonaqueous media (no precise data on this point are available), it seemed desirable to extend the study of these salts as solutes initially by making observations on some of their properties in mixed water-methanol solvent systems. The results of one such investigation are reported here. SULFAMATE SOLUTIONS

The sulfamate salts were prepared from Eastman Kodak white label sulfamic acid and the corresponding metal carbonate; after reaction they were purified 1 This paper is based upon research performed under Contract No. W36-039-sc-32265 for the U.S. Army Signal Corps.

1534 MAGNETIC STUDY OF SOME BORON COMPOUNDS The

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