Huygens Institute - Royal Netherlands Academy of Arts and Sciences (KNAW)
Citation:
F.A.H. Schreinemakers & , On the Quaternary systems KCl-CuCl2-BaCl2-H20, in:
KNAW, Proceedings, 15 I, 1912, 1912, pp. 467-472
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467
Ohemistry. - "On t!te Quaternary system: KCl-CuCl,-BaCI,H,O." By Prof. F. A. H. ScHRElNEMAKERS and Miss W. C. DE BAAT.
(Communieated in tbe meeting of September 28, 1912).
In the previous articles 1) we al ready discussed the equilibria
occurring at 30° in the quaternary systems:
NaCl - CuCl, - HaCI, - H2 0
and
NH 4 CI - CuCl, - BaCI, - HsO
In tbe first sy!'ltem no double salt is formed, in the second
oecurs tbe double salt CuCI, .2 NH 4CI . 2 H,O. As in tbe system :
KCI- CuCI, - BaCl, - H,O
tw,Q double salts may appear, we have now investigated this system
also.
Tbe two double saUs are:
Dt.u= CuCI,. 2 KCI. 2 H,O
D1.l
CaCL. . KCI ,
and
The equilibria occurring bave been mvestigated at 40° and 600;
these temperatures have been chosen purposely because at the first
temperature (JOO) only one of the double salts (Dl.2.2) still occurs;
at the other temperature (60°) hoth double salts appeal'.
In the ternary system KCI- BaCI, - H,O oecu!' as solid substances, at 40° and 60° KCI and BaCI, , 2 H,O so that the isotherms
also consist of two saturation lines.
The monovariant (P) equilibria occurring in the ternary system
KCI - ClICI, - H,O have been described previously by W. MEYERHOFFER 2); the isotherm of 30° lias been determined oy H. FILIPPO 3),
From these investigations it foJlows that below 57°, in addition
to KCI and CuCI,.2H.O also occurs tbe double salt D1.2.2, between
57' and 92° the double salts D1.2.2 and Du and above 92° only the
double salt Du.
Tbe isotherm of 400 therefore consists of the saturation lines of:
KCI ,CuCl,.2H,O and Dl.2.2, that of 60:' of the satUl'ation 1ines of
KCJ , CuCl,.2H,O, Dl.2.2 and Du.
Tbe equilibria appearing in the quaternal'y system may be represented in space, in tbe weU known manner with the aid of a tetrahedron, whose four apexes indicate tbe four components: KCI, CuCI s '
HaCI, and water. In Figs, 1 and 2 is found a projection of the
=
1)
t)
F. A. H. ScHRElNllJlAKERS and Miss W. C. DE BAAT. Chem. WeekbJ. 1908.
W. MEYERHOFFER, Z.. f. Phys. Chem. S 336 (1~).
..
"
"""
a) H, FlLlPPo. Not yet published.
, , 5 97 (1890).
31*
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468
spacial l'epresentation on tbe sidt' plane KCI-RaCI, -CuCJ, "or- the
tetl'ahedron which projection may be easily deduced in tbe weil
known manner from the representation in space 1).
Fig. 1 gives a schematic representation of the equilibria oecurring at 40°.
The equilibria occurring in the ternary system BaCl,-CuCl,"\Vater are represented hy the curves ab and bc situated on the
side plane BaCI,-CuCI, -Water.
ah is the saturation line of the CuCl,.2H,O
be " "
"
" " " BaCl,.2H,O
The solution b is saturated with both salts.
Fig. 1.
Tbe E:quili bria occl1rring in the ternary system : KCI-BaCI, - Water
are l'epresented by the curves cd and de situated on the side plane :
KCI-BaCI,-Watel'.
cd is tbe saturation line of the BaCl,.2H,O
de " "
"
" " KCI.
Tile soJution d is satl1rated with both saIts.
The curves el, (g and ga situated on the side plane KCI-CuCJ,Watel' represent the equilibria in tbe ternary system Kel-CuCI,-Water.
e f is the saturation line of the K Cl.
j' g " " "
" " Dl.22.
ga"""
" " Cu Cl, . 2 H, O.
Hence the soluhility Hne of the double salt D1.2.2 = Cu Cl, . 2 K Cl .
2 H2 0 is limiled in" point f by the occurrence of so1id K Cl and in
point g by the occurrence of solid Cu Cl, . 2 H, O.
1) Z. f. Phys. Chem. 65, 563 (1909).
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469
In the quaternary system occur solutions saturated with ODe, two
and thl'ee solid substances.
Those saturated with one solid substance only are repl'esented. by
aplane, the saiuration plane of tbat substance.
Plane 1 or ab It 9 is the saturation
plane of the Cu Cl: . 2 H~ O.
" II " e d i f " "
"
" " " K Cl.
.. III ,. c b Ai d " "
"
" " " Ba Cl z . 2 Hz O.
" IV " I 9 h i " "
,.,
" " " D1.2.2.
The int.et'Secting lines of these saturation plan es indicate the so}u·
tions saturated with two solid substances; th us we find:
Curve bit is the saturation
curve of
CuCI,.2H,O +BaCl,.2H,O.
KCI+BaC1 2 ·2H.O.
"
"
"
"
KCl+Dl.2.2.
"
"
" "
"
Dl.2.2 +BaCl •. 2H.O.
"
"
"
"
"
,
Dl.2.2 + CuCI,,2H.O.
"
"
"
"
The solutions satllrated with three solid substances al'e represented
by the points of intersection of the saturation planes;
,,
di
"
fi
"
ih
"
hg
"
"
Point h is the saturation point of CuCI •. 2H,O+BaCI •. 2H zO+D1.2.2.
" " " KCI+BaCI,.2H,0+D 1.2.2.
" ~""
Ir we remember that the equilibria represented in Fig. 1 apply
only to one definite temperatUl'e Tand to one definite pressure P,
we notice occurrence of the following equilibria:
A. Invariant (P. T.) equilibria (n Components in n phases)
1. binary:
the point a, c and e;
2. tel'nary:
" " lI, d, f and g;
3. quaternary: "
" i and lt.
B. Monovariant (p. T.) equilibria (n Components in n-1 phases)
1. ternary: the Curves ab, be, cd, de, eJ, Jg and ga.
2. quaternary: the Curves bit, Id, id, ij and gh.
C. Divariant (P. T) equilibria (n Components in n-2 phases.
1. quaternary: the planes 1, 11, III and IV.
The equilibria occurring at 60° are represented schematically in
fig. 2; this is distinguished from fig. 1 in so far th at bet ween
the saturation plane 1 'and 1 V of fig. 1 another saturation plane V
bas introduced itself so that the following saturation planes oecur.
Plane f,or a bIk, tbe saturation plane of CuCl s 2H,O
"
"
"
u
11 .. edil."
.,
lIJ "eblhid,,,
"
1 V ",I gh i, " "
V ,,9 h l k
"
."
-4-
" " KOl
" " BaOls 2H,0
" " Dl.2.2'
" " Du
470
If we compare tbe figs 1 and 2 we notice tbat tbe equilihria in
fbe two ternary systems CnCI,-BaCII-Water and KCI-BaCI,-Water, do not sbow appreciabIe differences at 400 and 60°, but that
these are observed in the ternary system CuClt-Kel-Water and
in tbe quaternary system.
At 40° (Fig. 1) the isotherm of tbe ternary system KCI
CuCI,-H 2 0 consists of:
ej, the saturation line of the KCI
jg,,,
"
..""
Dl.2.2
and ga,..
"
" " " CuCI, 2H,O
whereas this consists at 60°, (Fig. 2), of:
Fig. 2.
ej, fhe saturation line of the KCI
jg,,,
..
" " " D 1.2.2
gle,,,
"
" " " Dll
and /ca,,,
"
" . . " CIlCI,.2H,O
Whereas at 4O~ only 5 qllaternary satllration curves oecur, Beven
al'e {ound at 60°, l1ameIy.
+
Curve bl, the saturation curve of CuCI,. 2H,O
BaCI, . 2H,O
"
di,,,
..
" " KCI
BaCI, . 2H,O
" ji,,,
"
.,,, KCI D 1.2.2
"
hi,,,
"
" " BaCI,. 2H,O
D1.2.2
"
hg,,,
"
" " Dl.2.2 D1.l
"
hl,,,
"
" " Dl.l
BaC1, . 2H,O
"
Id,,,
"
" " D1.l
(luCl, . 2H,O.
The saturation curve gIt of fig. 1 (at 40j is, therefore replaced
in fig. 2 (at 6(0) by fhe three satnration curves gh, hl and lic.
At 40° (fig. 1) we find only two, at 600 (fig. 2) however, throe
quaternary satumtion points, namely:
+
+
+
+
+
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+
471
+
+
BaCI, . 2H,O
D1.2.2
Point i, the saturation point of KCI
., !L,
" "BaCl, . 2H,O
Dl.2.2
Dt.t
"
"
"
"BaCl,.2H
0
+
CuCI,.2H,O.+
Dl.l
2
" I,
"
+
+
"
As the equilibria represented in fig. 2 only apply to one definite
temperature T and one definite pressure P, we have at 60° tbe
following equilibria:
A. lnvariant (P. T) equilibria.
J. binary:
the point a, c and e.
2. ternary:
"
"b, d, f, ,g and k,
3. quaternary:"
" i , hand I.
B. Monovru'iant (P. T) equilibria.
1. ternar)' :
the curves ab, he, cd, de, el, Ig, ,gk and ka.
2. quaternary:"
"
bi, Id, lil, ,gh, lti, li and id
C. Divariant (P. T) equilibria.
1. quaternary: tbe planes I, lI, 111, IV and V .
•
It is evident that bet ween tbe Figs. 1 and 2 tbere exist transition forms, wbich must occur between 40° and 60°. If we start
from fig. 2 and lower tbe temperatUl'e, t he saturation sUl'face V gets
smaller until at 57° the points 9 and k coincide. Tbe saturation surface
then has a triangl11ar form of which one apex rests against the side
plane W-CuCI,--KCI of the tetl'ahE.'dron. As in th is apex the
satnration surfaces I, IV, and V meet, tbe equilibrium:
+
+
Cu CJ2.2H20
D1.2.2
Dl.l
OCCllrs in the ternary system KCI - CuCl, W nter at 57).
On lowering tbe temperature still furthm' the saturation surface V
becomes smaller still and surrounded by the saturation surfaees l, IJl
ànd IV to finally disappear in a point within tbe tetrabedron, 80
that tbe relations drawn in fig. 1 oceur, The moment the saturation
surface V disappears, or rather that it becomes metastable, the
surfàces I, 111, 1 V, and V pass throllgh one point so tbat only one
single point of the surface V represents a stabie solution. This then
signifies tbat in the quaternary system occurs the invariant (P) equilibrium :
Ba C12·2H20
+ Cu C12.2H20 + Dl.2.2 + DI.1 + Solution.
This as deduced from the thermic determinations, bappens at
± 55.7°.
Hetween tbe above 5 phases a phase reaction may take place at
~5.7°; on increase. or decrease of heat,
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472
If, for tbe sake of brevity, we eall Ba Clz.2HzO
2 H2Û = Cuz, the reaction is then:
= BR2 and Cu Clz.
+ Cuz + Dl.z.2 ~ DI.1 + Solution
,
I Hsz + Cuz + DI + Sol.
Ba2 + Cuz + Dl.2.2 + Sol. B + D
+ D . + Sol
B +C +D
+
D
az
1.2.2
~
U2
1.2.2
i Cn + D
+ D + Sol
Ba!!
1
I
1.1
I
2
i
1.2.2
1.1
1.1
•
•
Hence, of the invariant (p) equilibrium two mono\'al'iant (P)
procood to lower and three to higher temperatnres, or if we only
consider the systems in which a solution oc('urs, one to lower and
three to higher temperatures.
The system procooding to lower temperatm'es: Baz
Cuz
D1.2.2
sol. still exists at 40° and is. represented in fig. 1 by the
D1.2.2
point lt. The system proceeding to higher tempt:'ratures: CU2
D1.1
solution terminates at 57°, wben tbe solution only still
contains tbe three components CuCI2, KCI and water.
The other two systems proceeding to higher temperatures still
0
exist at 60 ; the solution of the system Ba2 + GU2
DI.1 +solution
is represented in fig. 2 by the point land that of the system:
HaCJ2
D1.2.2 + DI.I is indicated in fig. 2 hy the point h.
+
+
+
+
+
+
+
+
Chemistry. - (, Tlte .<;y.çtem HgCl,-OuCl,-H,O." Hy Prof. F.
A. H. ScHREINEMAKERS and J. C. THONUS.
(Communicated in the meeting of September 28, 1912).
In order to ascertain whether or not the salts HgCl, and CnCI,
form a don bIe salt, the isotherm of 35° was determined; tbe l'e..",ult
of this investigation is that, at 35° no double salt was found hut
that the salts HgCl. and CuCI,. 2H,0 can exist by the side of
eacb other.
In fig. 1, the experimentally
determined isotherm of 35° is
represented schematically ; the
apexes W, H6CI, and CuCI s represent the throo component..q , and
the point Cu, the hydrate CuCI •.
2 H.O.
w
Fig.!.
The isotherm consiats of the
two . branches ac and he; ac indicates the soJutions' wbich are
saturated with the hydrate CuCI •.
2 RjO, be those "Saturated with
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