Determination of the mean enthalpy of dissociation of arsenic-oxygen bonds in some arsenic (III) alkoxides

Article abstract of DOI:10.1006/jcht.1996.0118

The standard molar enthalpy of formation of arsenic alkoxides in the liquid phase, As(OR)₃ {R = ethyl (Et), n-propyl (Prⁿ), i-propyl (Prⁱ), n-butyl (Buⁿ), and i-butyl (Buⁱ)}, was determined through reaction-solution calorimetry in chloroform based on the reaction: As(NEt₂)₃(1) + 3ROH(1) = As(OR)₃(1); Δ_solH_m^o at T = 298.15 K. This series of alkoxides gave the following molar enthalpy of formation Δ_fH_mo values: -(758.1 ± 9.0) kJ · mol^-1, -(774.3 ± 9.0) kJ · mol^-1, -(809.8 ± 9.0) kJ · mol^-1, -(828.8 ± 8.9) kJ · mol^-1, and -(863.4 ± 8.9) KJ · mol^-1, respectively. The standard molar enthalpies of vaporization Δ_vapH_m (47.9 ± 1.1) kJ · mol_-1, (51.2 ± 1.8) kJ · mol^-1, (80.1 + 0.9) kJ · mol^-1, (64.0 ± 1.8) kJ · mol^-1 and (75.7 ± 1.2) kJ · mol^-1, were obtained for the same sequence of alkoxides, by means of differential scanning calorimetry. By combining the preceding values with the standard molar enthalpy of formation of the alkoxide Δ_fH_m in the liquid phase, the standard molar enthalpy of formation of these compounds in the gas phase was obtained as -(710.2 ± 9.0) kJ · mol^-1, -(723.1 ± 9.1) kJ · mol^-1, -(729.3 ± 9.0) kJ · mol^-1, -(764.8 ± 9.1) kJ · mol^-1, and -(787.7 ± 9.0) kJ · mol^-1, respectively. From these values, the mean enthalpy of dissociation of the arsenic-oxygen bond 〈D_m〉(As-O) was calculated for the sequence of the above alkoxides to give: (320 ± 5) kJ · mol^-1, (301 ± 5) kJ · mol^-1, (292 ± S) kJ · mol^-1, (293 ± 5) kJ · mol^-1, and (294 ± 5) kJ · mol^-1. The linear correlation between the standard molar enthalpies of formation of the liquid alkoxides Δ_fH_m{As(OR)₃,1} and the respective alcohol Δ_fH_m(ROH,1), suggests that these thermochemical data can be assessed for a series of normal and iso chain alcohols.

Full text of DOI:10.1006/jcht.1996.0118

J. Chem. Thermodynamics
28, 1359–1367
Departamento de Quımica, CCEN, Universidade Federal da Paraıba,
58059-900 Joao Pessoa, Paraıba, Brasil
a
Instituto de Quımica, Universidade Estadual de Campinas, Caixa Postal 6154,
13083-970 Campinas, Sao Paulo, Brasil
The standard molar enthalpy of formation of arsenic alkoxides in the liquid phase,
As(OR)3 {R = ethyl (Et), n-propyl (Prn), i-propyl (Pri), n-butyl (Bun), and i-butyl (Bui)}, was
determined through reaction–solution calorimetry in chloroform based on the reaction:
As(NEt2)3(l) + 3ROH(l) = As(OR)3(l); DsolHm° at T = 298.15 K. This series of alkoxides
gave the following molar enthalpy of formation DfHm° values: −(758.1 2 9.0) kJ·mol−1
,
−(774.3
2 , −(809.8 2 , −(828.8 2 , and
9.0) kJ·mol−1 9.0) kJ·mol−1 8.9) kJ·mol−1
−(863.4 2 8.9) kJ·mol−1, respectively. The standard molar enthalpies of vaporization DvapHm
(47.9 2 1.1) kJ·mol−1, (51.2 2 1.8) kJ·mol−1, (80.1 2 0.9) kJ·mol−1, (64.0 2 1.8) kJ·mol−1
and (75.7 2 1.2) kJ·mol−1, were obtained for the same sequence of alkoxides, by means of
differential scanning calorimetry. By combining the preceding values with the standard
molar enthalpy of formation of the alkoxide DfHm in the liquid phase, the standard molar
enthalpy of formation of these compounds in the gas phase was obtained as
−(710.2 2 9.0) kJ·mol−1, −(723.1 2 9.1) kJ·mol−1, −(729.3 2 9.0) kJ·mol−1, −(764.8 2
9.1) kJ·mol−1, and −(787.7 2 9.0) kJ·mol−1, respectively. From these values, the mean enthalpy
of dissociation of the arsenic–oxygen bond ꢀDmꢁ(As–O) was calculated for the sequence of the
above alkoxides to give: (320 2 5) kJ·mol−1
,
(301 2 5) kJ·mol−1
,
(292 2 5) kJ·mol−1
,
(293 2 5) kJ·mol−1, and (294 2 5) kJ·mol−1. The linear correlation between the standard molar
enthalpies of formation of the liquid alkoxides DfHm{As(OR)3,l} and the respective alcohol
DfHm(ROH,l), suggests that these thermochemical data can be assessed for a series of normal
and iso chain alcohols. 7 1996 Academic Press Limited
Due to the fact that alkoxides are formed by the replacement of the hydrogen of
the alcohol by a given metal, their physical properties depend not only on the
position of the metal in the Periodic Table, but also on the nature of the alkyl
group attached to the oxygen atom of the alcohol.(1, 2) Many of them are strongly
associated by intermolecular forces which are related to the alkyl groups, as
observed with alkali and lanthanides or volatile liquids in the form of monomers
a To whom correspondence should be addressed.
0021–9614/96/121359 + 09 $18.00/0
7 1996 Academic Press Limited

1360
A. G. de Souza, M. G. A. Brasilino, and C. Airoldi
for gallium, germanium, and arsenic.(2–4) Normally, alkoxides of lower members
of a given series are rapidly and completely hydrolysed by water to give the
respective alcohol. This hydrolysis in the presence of excess alkali has been explored
previously to determine some thermochemical results of methyl-, ethyl-, and
n-propyl-alkoxides of As (III).(5) Other determinations for ethyl-, n-butyl-, n-pentyl-,
and n-heptyl-alkoxides used the preceding procedure(5) associated with the enthalpies
of combustion.(6)
In spite of the importance of using arsenic in the various fields of science and
technology, mainly in microelectronics,(7, 8) only the alkoxides listed above have had
their thermochemical data determined.(5, 6) The precursors of these semiconductors
might be prepared as thin films from high-purity volatile arsenic compounds by
applying the conventional OMCVD methodology.(7–9) Therefore, the thermochemical
data of these types of precursors can lead to a better understanding of these
applications. The present study contributes some thermochemical results for
alkoxides with the general formula As(OR)3 {R = ethyl (Et), n-propyl (Prn), i-propyl
(Pri), n-butyl (Bun), and i-butyl (Bui)}. The standard molar enthalpy of formation of
these liquid compounds was determined from reaction–solution calorimetry, by
means of exchange reactions of the amido group of tris(diethylamido)arsenic (III),
As(NEt2)3, with the respective alcohol in chloroform. This enthalpy showed a linear
correlation with the standard molar enthalpy of formation of the respective alcohols.
The mean enthalpy of the arsenic–oxygen bond has also been determined.
Arsenic trichloride (Carlo Erba), diethylamine (Riedel), and carbon disulphide
(Merck) were purified by distillation. The solvents diethyl ether, n-hexane, and
chloroform (Merck) were treated with (calcium chloride + metallic sodium) and
distilled. The alcohols were refluxed over calcium oxide, distilled, refluxed over
magnesium and iodine, and then fractionally distilled.
The precursor calorimetric reagent As(NEt2)3 was prepared by adding
diethylamine dropwise over a solution of the arsenic trichloride in ether,
n{(C2H5)2NH}/n(AsCl3) = 6, under a dry nitrogen atmosphere at T = 263 K. After
filtration, the solvent was eliminated under reduced pressure and the resulting oily
liquid was purified by successive distillations.(10) The existence of a sharp boiling
temperature at T = 528 K and the main infrared stretching bands at 2975 cm−1
(C–H), 1003 cm−1 (C–C), 917 cm−1 (N–C), and 595 cm−1 (As–N), are consistent
with the purity of the products.
The alkoxides As(OR)3 (R = Et, Prn, Pri, Bun, and Bui) are moisture-sensitive.
Therefore, all syntheses and subsequent manipulations were conducted under a
nitrogen atmosphere. All preparations followed the same procedure, as described
previously.(11) Briefly, arsenic trichloride was slowly added to a solution containing
the desired alcohol and triethylamine dissolved in ether in an (ice + salt) bath
at T = 278 K. During the addition, a large amount of ammonium chloride was
formed, which was filtered under reduced pressure. The filtrate was purified through
successive distillations. All alkoxides are transparent liquids and extremely sensitive

Arsenic-to-oxygen bonds in arsenic (III) alkoxides
1361
to hydrolysis. The proton n.m.r. spectrum, g.c., and mass spectrometry indicated the
high purity of these compounds.
The reaction–solution calorimetric measurements were performed in an LKB
8700 isoperibolic precision calorimetric system. The ampoules were prepared by
using a microsyringe in a dry box under gaseous nitrogen. The dry vessel was quickly
loaded with calorimetric solvent in a dry atmosphere. In a typical experiment, thin
glass ampoules were loaded with 5.0 mg to 7.2 mg of sample, sealed under dry
conditions, and broken into 0.10 dm3 of chloroform at T = 298.15 K. For each
individual determination of a given standard molar enthalpy of dissolution, at
least five ampoules of each reactant were broken into the calorimetric solvent.
The enthalpy of empty ampoule breaking and corrections for solute or solvent
vaporization were found to be negligible.(12) Details of the operational procedure,
the calculation method, and the accuracy of the instrument have been described
previously.(13)
The enthalpy of vaporization of the alkoxides was obtained by means of a
differential scanning calorimeter, Shimadzu model DSC-50, under dry nitrogen
flow, with a heating rate of 0.17 K·s−1
.
The g.c. was performed in a Hewlett–Packard model 5988-A instrument. The
room-temperature proton n.m.r. spectrum was obtained in a Varian model EM 360
apparatus. The infrared spectrum of a film on sodium chloride windows, in the
(4000 to 600) cm−1 region, was obtained in a Bomem model MB-102 instrument.
Special care was taken in order to obtain high-purity alkoxides and amido
compounds. Thus, the series of alkoxides As(OR)3 was characterized through the
boiling temperature interval at ambient atmosphere, by mass spectrometry, and
proton n.m.r. spectrum. The results are presented in table 1. The unique peak in
the g.c. confirms the quality of the products.
The mass spectra fragmentations showed, for all compounds, a series of
characteristic peaks with the same relative intensity, indicated in table 1, as observed
for other alkoxides of this group of elements.(14) On the other hand, the parent
TABLE 1. Boiling temperature interval, DT, relative mass spectrometric intensities I/I° at 11.2 aJ;
multiplet centered proton n.m.r. signals Dd and coupling constants J for the alkoxides
As(OEt)3
As(OPrn)3
As(OPri)3
As(OBun)3
As(OBui)3
549 to 551
DT/K
443 to 446
518 to 520
480 to 482
573 to 578
I{As(OR)3}/I°
I{As(OR)2}/I°
I{As(OR)}/I°
I(As(OR)/I°
Dd(CH)
11
100
98
42
4.14
4
100
46
1
100
87
56
4.36
1
100
100
30
100
38
53
1.70
3.5
0.82
4.0
11
Dd(CH2)
3.65
0.85
8.0
Dd(CH3)
1.35
8.0
1.34
7.0
0.95
6.0
J/Hz

1362
A. G. de Souza, M. G. A. Brasilino, and C. Airoldi
ion was observed with low intensity, being absent in the case of As(OBui)3. The
1H n.m.r. spectra in deuterated chloroform at room temperature showed chemical
shifts in low field in relation to the internal tetramethylsilane as a reference. From
signal integration, the groups attached to the oxygen atom of the alkoxides were
quantitatively assigned.(15) The results are listed in table 1. The spectra did not show
any coupling between arsenic and hydrogen atoms. This, as well as the narrow
interval of boiling temperatures, confirms the high purity of these compounds.
The standard molar enthalpies of reaction DrHm° for liquid alkoxides As(OR)3
(R = Et, Prn, Pri, Bun, and Bui) were obtained by considering the reaction–solution
calorimetric determinations at T = 298.15 K, based on the general thermochemical
reaction:
As(NEt2)3(l) + 3ROH(l) = As(OR)3(l) + 3HNEt2(l).
(1)
The standard molar enthalpies for this general reaction were obtained by
measuring the enthalpy of dissociation of reactants and products, maintaining an
appropriate sequence. In all these dissolutions, strict control of the stoichiometries
in each step of the calorimetric reactions was used, with the objective that the
dissolution of the reactants had the same composition as those of the products
of the above-mentioned general reaction. From the sequence of dissolutions
in chloroform, listed in table 2, values of DrHm° were calculated by applying a
TABLE 2. Standard molar enthalpies of dissolution DsolHm° of alkoxides in chloroform (HCCl3) at
T = 298.15 K
D
solHm°
Reagent
Solvent
Solution
No. of expts
kJ·mol−1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
As(NEt2)3(l)
3C2H5OH(l)
As(OEt)3(l)
3HNEt2(l)
As(NEt2)3(l)
3n-C3H7OH(l)
As(OPrn)3(l)
3HNEt2(l)
As(NEt2)3(l)
3i-C3H7OH(l)
As(OPri)3(l)
3HNEt2(l)
As(NEt2)3(l)
3n-C4H9OH(l)
As(OBun)3(l)
3HNEt2(l)
As(NEt2)3(l)
3i-C4H9OH(l)
As(OBui)3(l)
3HNEt2(l)
3CS2(l)
As(NEt2)3(l)
As(S2CNEt2)3(cr)
HCCl3
A1
HCCl3
A3
HCCl3
B1
HCCl3
B3
HCCl3
C1
HCCl3
C3
HCCl3
D1
HCCl3
D3
HCCl3
E1
HCCl3
E3
HCCl3
F1
HCCl3
A1
A2
A3
A4
B1
B2
B3
B4
C1
C2
C3
C4
D1
D2
D3
D4
E1
E2
E3
E4
F1
F2
F3
6
5
6
6
5
5
6
6
5
5
6
6
6
6
5
5
5
5
5
6
5
6
5
−114.62 2 0.08
9.78 2 0.09
−13.30 2 0.25
−16.97 2 0.09
−114.13 2 0.15
14.02 2 0.10
−17.66 2 0.32
−20.10 2 0.06
−114.35 2 0.33
17.16 2 0.29
−14.08 2 0.16
−21.94 2 0.31
−114.55 2 0.05
8.01 2 0.04
−31.29 2 0.61
−28.23 2 0.24
−114.05 2 0.13
10.53 2 0.07
−23.19 2 0.09
−32.02 2 0.22
1.06 2 0.02
−183.80 2 1.28
9.74 2 0.10

Arsenic-to-oxygen bonds in arsenic (III) alkoxides
1363
convenient general thermochemical cycle(16) to equation (1), as indicated below,
where DrHm(5) = 0 was obtained when ampoules of mixtures of reactants were
broken into the solution of product.
As(NEt2)(l) + HCCl3 = soln X1;
3ROH(l) + soln X1 = soln X2;
As(OR)3(l) + HCCl3 = soln X3;
3HNEt2(l) + soln X3 = soln X4;
soln X2 = soln X4.
(2)
(3)
(4)
(5)
(6)
For X = A, B, C, D, or E the individual enthalpic values listed in table 2
were derived to obtain DrHm = DrHm(2) + 3·DrHm(3) − DrHm(4) − 3·DrHm(5).
The same procedure was used to determine the standard molar enthalpy DrHm°
of the following reaction:
As(NEt2)3(l) + 3CS2(l) = As(S2CNEt2)3(s).
(7)
The standard molar enthalpy of this reaction was calculated by considering
the individual steps of the enthalpies of dissolution, which are listed in table 2.
From these values, the standard molar enthalpy of formation of the amido
compound was first calculated. For this determination, the standard enthalpy
of formation of the respective thiocarbamate compound obtained previously
was used, and for the auxiliary results listed in table 3, by means of the
expression:
DfHm°{As(NEt2)3,l} = DrHm° + DfHm°{As(S2CNEt2)3,s} − 3·DfHm°(CS2,l).
(8)
TABLE 3. Auxiliary standard molar enthalpies of formation
DtHm°
Compound
HNEt2(l)
As(S2CNEt2)3(cr)
CS2(l)
C2H5OH(l)
n-C3H5OH(l)
i-C3H7OH(l)
n-C4H9OH(l)
i-C4H9OH(l)
As(g)
Reference
kJ·mol−1
−103.7 2 1.2
−104.7 2 7.6
89.8 2 0.8
−288.2 2 0.4
−302.6 2 0.5
−318.1 2 0.5
−327.3 2 0.4
−342.6 2 0.7
302.5 2 0.2
−17 2 4
17
18
17
17
17
17
17
17
19
20
20
20
20
20
C2H5O(g)
n-C3H7O(g)
i-C3H7O(g)
n-C4H9O(g)
i-C4H9O(g)
−41 2 4
−52 2 4
−63 2 4
−69 2 4

1364
A. G. de Souza, M. G. A. Brasilino, and C. Airoldi
TABLE 4. Summary of the thermochemical results
DrHm°
DfHm°(l)
D
vapHm°
DfHm°(g)
ꢀDmꢁ(As–O)
Compound
kJ·mol−1
kJ·mol−1
kJ·mol−1
kJ·mol−1
kJ·mol−1
As(OEt)3
As(OPrn)3
As(OPri)3
As(OBun)3
As(OBui)3
As(NEt2)3
−21.07 2 1.28
5.89 2 0.50
17.03 2 1.32
25.46 2 0.95
36.79 2 0.71
−190.36 2 1.30
−758.1 2 9.0
−774.3 2 9.0
−809.8 2 9.0
−828.8 2 8.9
−863.4 2 8.9
−183.5 2 8.1
47.9 2 1.1
51.2 2 1.8
80.1 2 0.9
64.0 2 1.8
75.7 2 1.2
−710.2 2 9.0
−723.1 2 9.1
−729.5 2 9.0
−764.8 2 9.1
−787.7 2 9.0
320 2 5
301 2 5
292 2 5
293 2 5
294 2 5
From this determination, the standard molar enthalpy of formation of the liquid
alkoxide is based on equation 7, through the following expression:
DfHm°{As(OR)3,l} = DrHm° − 3·DfHm°(HNEt2,l) +
DfHm°{As(NEt2)3,l} + 3·DfHm°(ROH,l). (9)
Auxiliary data(17–20) listed in table 3 were used to calculate the standard molar
enthalpies of formation of liquid alkoxides, which are given in table 4.
To determine the mean enthalpy of dissociation of the arsenic–oxygen bond, it is
necessary to have information about these compounds in the gas phase.(16) The molar
enthalpy of vaporization DvapHm° of these alkoxides was obtained by differential
scanning calorimetry,(16) where the value listed in table 4 is the mean of at least
three determinations. Consequently, the standard molar enthalpies of formation
of the gaseous compounds can be calculated by the following expression, whose
values are also listed in table 4.
DfHm°{As(OR)3,g)} = DfHm°{As(OR)3,l)} + DvapHm°{As(OR)3}.
(10)
The mean dissociation enthalpy of the arsenic–oxygen bond for this series of
compounds can be calculated from the standard molar enthalpies of formation
of the alkoxides in the gas phase (table 4), from the auxiliary results of the
standard molar enthalpies of formation of As(g) and the respective alkoxide radicals
in the gas phase listed in table 3. As a result, the values correspond to one-third of
the standard molar enthalpy of the following reaction:
As(OR)3(g) = As(g) + 3OR(g).
(11)
Although the determination of ꢀDmꢁ(As–O) values depends on the standard molar
enthalpy of formation of the alkoxide in the condensed phase, the enthalpy of
sublimation and the auxiliary data used in the calculation can affect the final value.
For example, the series of mean dissociation enthalpies for arsenic–oxygen bonds
obtained here can be compared with those of the same compounds obtained by
different authors, either derived from the standard molar enthalpies of formation
from enthalpies of combustion(6) or enthalpies of hydrolysis of the alkoxides in
aqueous sodium hydroxide.(5) In this case, the first ꢀDmꢁ(As–OEt) value determined
was recalculated taking into account the updated values, listed in table 3,
which caused a change from (270 2 6) kJ·mol−1 to (303 2 4) kJ·mol−1. Another

Arsenic-to-oxygen bonds in arsenic (III) alkoxides
1365
more recent determination(6) presenting a value of (290 2 2) kJ·mol−1, has also been
changed after using these auxiliary results to (305 2 4) kJ·mol−1. Both values
are comparable to the present value (320 2 5) kJ·mol−1. The same procedure
was used for the normal propanol(5) and butanol(6) compounds, which changed
from (278 2 11) kJ·mol−1 and (291 2 2) kJ·mol−1 to (307 2 5) kJ·mol−1 and
(304 2 5) kJ·mol−1, respectively. Current results for the same alkoxides are
(301 2 5) kJ·mol−1 and (293 2 5) kJ·mol−1, respectively.
The mean enthalpy of dissociation of the arsenic–oxygen bond, ꢀDmꢁ(As–O), in
the series of compounds decreases with the increase of the number of carbon atoms
in the radical attached to oxygen, when the normal chain of the alkoxides is
considered. Therefore, the sequence of results gives for ꢀDmꢁ(As–OR) the order:
OEt q OPrnꢁOBun. Probably, this fact is related to the electronic effect of the radical,
which decreases in the same direction. A direct comparison involving normal and
branched chains showed that ꢀDmꢁ(As–O) values are higher for the normal propyl
alcohol. However, for butyl alkoxides, both normal and iso chains gave the same
results. For a series of titanium alkoxides(21, 22) of the type Ti(OR)4, the mean enthalpy
of dissociation of the titanium–oxygen bond is not significantly affected by the
nature of the alkyl group, and these values are at least 100 kJ·mol−1 higher than
740
Et
760
780
800
820
840
860
880
Prn
Pri
Bun
Bui
340
350
330
320
310
300
290
280
–∆fHom (ROH, l)/(kJ·mol–1
)
FIGURE 1. The standard molar enthalpies of formation of arsenic alkoxides against the standard molar
enthalpies of formation of the corresponding alcohols.

1366
A. G. de Souza, M. G. A. Brasilino, and C. Airoldi
those obtained with arsenic alkoxides. Conversely, some results involving couples
of alkoxides of different metals like vanadium and chromium,(23) zirconium and
hafnium,(24) and niobium and tantalum,(25) showed that ꢀDmꢁ(M–O) for those
compounds increased significantly with the increase of the atomic number of the
metal. This behaviour suggests that the nature of the metal affects the mean enthalpy
of dissociation of the metal–oxygen bond in a more important way than the
carbon chain of the alcohol.
The results listed in table 4 were submitted to a consistency test involving a plot
of enthalpies of formation of liquid alkoxides against the respective enthalpies of
formation of the alcohols in their reference state, i.e. the compounds in the reference
state at T = 298.15 K and p = 101.325 kPa. This type of plot was firstly used to
assess the reliability of thermodynamic data for many families of compounds.(26)
Good linear behaviour is shown in figure 1, with a linear correlation coefficient of
0.9936, to give:
DfHm°{As(OR)3,l}/(kJ·mol− 1) = (1.982 2 0.130)·DfHm(ROH,l)/(kJ·mol− 1) −
(180.8 2 41.2) kJ·mol−1
. (12)
The alkoxides formed by normal and iso chain alcohols show a good fit for this
correlation, as observed for ionic sodium alkoxides.(27) In conclusion, these groups
showed a similarity in bonding, and the steric and electronic effects for this series
of alkoxides, which could eventually be used to distinguish these compounds, did
not cause any difference in behaviour. In spite of the lack of thermochemical
data involving these alkoxides, it is possible to use this linear correlation to assess
or to estimate new standard molar enthalpies of formation of other alkoxides.
The authors are indebted to FINEP and PADCT/CNPq for financial support.
REFERENCES
1. Bradley, D. C.; Mehrotra, R. C.; Gaur, D. P. Metal Alkoxides. Academic Press: London.
2. Bradley, D. C. Prog. Inorg. Chem. 2, 303–361.
3. Bradley, D. C. Adv. Inorg. Chem. Radiochem.
4. Wardlaw, W. J. Chem. Soc. 4004–4014.
5. Charnley, T.; Mortimer, C. T.; Skinner, H. A. J. Chem. Soc.
.
15, 259–322.
1181–1184.
6. Shaposhnikov, V. V.; Larina, V. N.; Tel’noi, V. I.; Grinberg, E. E. Russ. J. General Chem.
63,
1587–1589.
7. Gorcharov, E. G.; Popov, A. E.; Zavrazhnov, A. Y. Inorg. Mater.
8. Cowley, A. H.; Benac, B. L.; Ekerd, J. G.; Jones, R. A. J. Am. Chem. Soc.
31, 535–546.
110, 6248–6249.
9. Lum, R. M.; Klingert, J. K.; Lamont, M. G. Appl. Phys. Lett.
50, 284–286.
10. Moedritzer, K. Chem. Ber.
11. Moedritzer, K. Inorg. Synth.
92, 2637–2640.
11, 181.
12. Sunner, S.; Wadso
13. Roca, R.; Chagas, A. P.; Airoldi, C. J. Solution Chem.
14. Brill, T. B.; Campbell, N. C. Inorg. Chem. 12, 1884–1888.
15. Budrikiewicz, H.; Djersasi, C.; Williams, D. H. Mass Spectrometry of Organic Compounds.
Holden-Day: San Francisco.
16. Airoldi, C.; Chagas, A. P. Coord. Chem. Rev.
17. Pedley, J. B.; Naylor, R. D.; Kirby, S. P. Thermochemical Data of Organic Compounds. Chapman
and Hall: London.
18. Airoldi, C.; Souza, A. G. J. Chem. Soc., Dalton Trans.
¨
, I. Science Tools
13, 1–6.
24, 39–50.
.
119, 29–65.
.
2955–2958.

Arsenic-to-oxygen bonds in arsenic (III) alkoxides
1367
19. Wagman, D. D.; Evans, W. H.; Parker, V. B.; Schumm, R. H.; Halow, I.; Bailey, S. M.; Churney,
K. L.; Nuttall, R. L. J. Phys. Chem. Ref. Data
20. McMillen, D. F.; Golden, D. M. Ann. Rev. Phys. Chem.
21. Bradley, D. C.; Hillyer, M. J. Trans. Faraday Soc.
22. Bradley, D. C.; Hillyer, M. J. Trans. Faraday Soc.
11, Suppl. 2.
33, 493–532.
62, 2367–2373.
62, 2374–2381.
23. Lappert, M. F.; Patil, D. S.; Pedley, J. B. J. Chem. Soc., Chem. Commun.
830–831.
24. Tel’noi, V. I.; Rabinovich, I. B.; Kozyrkin, B. I.; Salamatin, B. A.; Kir’yanov, K. V. Dokl. Chem.
205, 588–590.
25. Tel’noi, V. I.; Rabinovich, I. B. Russ. Chem. Rev.
46, 689–705.
26. Dias, A. R.; Martinho Simoes, J. A.; Teixeira, C.; Airoldi, C.; Chagas, A. P. Polyhedron
10,
1433–1441.
27. Leal, J. P.; Pires de Matos, A.; Martinho Simoes, J. A. J. Organomet. Chem.
403, 1–10.
(Received 13 September 1995; in final form 6 June 1996)
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