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The ammonolysis of zirconium(IV) chloride
SHORT COMMUNICATIONS
4or
The nearly regular periodicity of the rows composition-temperature conditions. suggests that in the case of either mechanism, the rate of motion of the boundaries is discontinuous. Occurrence of this phenomenon opens the possibility of studying in three dimensions the change in shape of an entire grain during grain boundary migration. Its shape could be revealed by successively removing layers of metal and etching to reveal the various positions of the grain boundaries. Union Carbide Metals Compalzy, Niagara
Falls,
N. Y. (U.S.A.)
W. F. SHEELY
1 A. I3. MICHAEL AND F. J. HUEGEL, Acta Met., 5 (1957) 339. 2 M.L. POCHON,C.R.MCKINSEY, R. A. PERKINS AND W. D. FORGENG, RegionalConference on Reactive Metals, hn. Inst. Mech. Engrs., 1958. Received May 23rd, 1960 J. Less-Common
The ammonolysis of zirconium(W)
Metals. 2 (1960) 399-401
chloride
Tensimetric studies made by FOWLES AND POLLARD’ showed that one mole of ammonium chloride was formed in the reaction of zirconium(IV) chloride with ammonia at -63” and -36°C. However, although these experiments suggested the formation of the ammonobasic zirconium(IV) chloride ZrC13(NHz), xNH3, this compound was not isolated, and in comparable experiments with vanadium(IV) chloride213, where VC12(NH2)2, xNH3 was formed under tensimetric conditions, ammonolysis was found to be more extensive when ammonium chloride was removed from the reaction mixture by washing it with liquid ammonia; VCl(NH&, 2NH3 was isolated in this way. Removal of ammonium chloride from the products of the ammonolysis of zirconium(IV) chloride does not, however, effect a greater replacement of chlorine atoms, and the ammonobasic zirconium(IV) chloride predicted in the tensimetric experiments can be isolated in almost quantitative yield. The small amount of zirconium (7%) found in the soluble portion probably results from the formation of complex zirconium anions similar to those found in the titanium(IV) halide-ammonia systemsd. Such complex formation would be small and would occur only in concentrated solutions of ammonium chloride. More extensive ammonolysis may sometimes be effected by heating the ammonobasic metal chlorides in vacua and then re-treating with liquid ammonias, but this is not very effective with zirconium(IV) chloride because a second zirconium-chlorine bond is only partially ammonolysed even when the product is heated to 100’. After such a treatment, however, more zirconium is found in the soluble portion, and it may be that the heating helps to break down the polymeric solid so that it dissolves in the presence of ammonium chloride. The ammonia which is attached to the ammonobasic zirconium(IV) chloride is J. Less-Common Metals. 2 (1960) 401-403
SHORT COMMUNICATIONS
402
steadily lost when the compound is heated in vacua, and at 100' the product has the composition ZrCL(NH2), NH3. The thermal decomposition (cf. Table II) is in complete agreement with that of the mixture. It is of interest to note that although ammonia forces the solvolysis of only one zirconium-chlorine bond, methylamine goes a stage further, which contrasts with the behaviour of titanium(IV) chloride where ammoniac and methylamine’ solvolyse three and two titanium-chlorine bonds respectively. These results may be correlated with the effect of the size of the metal chloride on the relative base strengths of ammonia and methylamines. Thus ammonia may be more basic than methylamine when titanium(IV) chloride is the reference acid since the four groups bonded to titanium should cause an appreciable amount of steric hindrance to the attacking ammonia or amine molecule. Since the zirconium atom is larger than the titanium atom, this steric hindrance should be less with zirconium(IV) chloride, and methylamine will be a better electron donor than ammonia.
EXPERIMENTAL
Zirconium(IV) chloride was prepared by the action of dry chlorine on heated zirconium strip (Murex), and purified by sublimation. Found: 25, 39.3; Cl, 61.0.ZrC14 requires: Zr, 39.2; Cl, 60.8%. Analyses for zirconium, chlorine, and nitrogen, were carried out as described previouslys. Reaction of zivconium(IV) chloride with liquid ammonia The white flocculent solid initially formed was filtered from the colourless solution and washed six times with 50 ml of liquid ammonia. Both soluble and insoluble products were kept in vacua for 6 h before being analysed; the soluble portion, which clung tenaciously to the sides of the vessel, was hydrolysed irt situ (cf. Table I, run I). In other experiments (cf. Table I, runs 2,3, and 4), the products were heated ilz vacua for 2 h after the second and fourth washes, and kept irz vacua for 12 h after the final wash; the total soluble product was heated to 50” for 12 h before analysis.
TABLE
Temp. of pumping RUB No.
I
after and and 4th washes (“Cl
No pumping
Insoluble %Zr
Y’Ct
O/o N
I
Soluble product
Product Zr
:
Cl
30.4 34.3 28.2
1.00 : 2.90
:
N
zr
Soluble Zr
:
CL
:
N
Total ZY
: 6.04
I.00
:
17.1
:
17.5
0.07
:
IO.9
2
20
32.1 35.8 26.1
1.0"
: 2.87 : 5.30
I.00
: II.9
0.10
3
50
31.6 34.6 27.6
1.00
: 2.82
I.00 : IO.1 : 10.0
0.20
4
100
34.1 33.7 26.6
1.00
: 2.54 : 5.08
: 6.74 : 7.76
0.33
: 5.69
1.00
J. Less-Common
Metals, 2 (1960) 401-403
403
SHORT COMMUNICATIONS
Samples of the insoluble products ious periods (cf. Table II).
were heated
TABLE
in vacua at 50” and then 100’ for var-
II
INSOLUBLEPRODUCTS,THERMALDECOMPOSITION Temperature
RU?& NO.
(“C)
Time
IO0
50
Y(,Zr q!Jl O/ON Zr
:
Cl
:
N
YhZr "SC1y/oN
z,
x.00 : 2.92
Cl
:
N
I
I?.
37.3
43.0
16.6
1.00 : 2.96 : 2.90
39.6
2
24
39.2
43.5
13.9
1.00 : 2.86 : 2.31
40.1 44.1 13.3
1.00
: 2.83 : 2.16
3
6
: 2.88 : 3.24
39.6 43.3 14.0
1.00
: 2.83 : 2.30
4
12
41.1 40.4 14.0
1.00
: 2.53 : 2.22
34.6 38.7 21.7 ---
1.00
-
44.9
We are grateful to the Esso Petroleum Company for providing (J.E.D.), and Messrs. Murex for a gift of pure zirconium metal. 1 2 3 4 5 6 7 8 9
:
(h) II.9
a maintenance
: I.96
grant
G. W. A. FOWLES AND F. H. PoLLARD,J.C~~~.SOC., (1953) 4128. G. W. A. FOWLES AND D. NICHOLLS,J. Chem.Soc.,(1958) 1687. G. W. A. FOWLES AND D. NICHOLLS, unpublished observations. G. W. A. FOWLES AND D.NICHOLLS, J. Chem,Soc.,(Ig59)ggo. H. MOUREU AND C. H. HAMBLET,~. Am.Chem.Soc.,59 (1937) 33. G. W. A. FOWLES AND F. H. POLLARD,~. Chem.Soc., (1953) 2588. R.T.COWDELL AND G. W. A. FOWLES,J. Chem. Sot., (1960) 2522. H. C. BROWN, J. Am. Ghem. Sot., 67 (1945) 378. J. E. DRAKE AND G. W. A.FowLEs,J. Chem.Soc., (1960) 1498.
J. E. G. W.
A.
DRAKE FOWLES
Dept. of Chemistry, The University, Southamptolz (Great Britain) Received J,
.bS.S-COmmO?Z
ibfc?tUk,
August
Qh, 1960
2 (1960) 401-403
4or
The nearly regular periodicity of the rows composition-temperature conditions. suggests that in the case of either mechanism, the rate of motion of the boundaries is discontinuous. Occurrence of this phenomenon opens the possibility of studying in three dimensions the change in shape of an entire grain during grain boundary migration. Its shape could be revealed by successively removing layers of metal and etching to reveal the various positions of the grain boundaries. Union Carbide Metals Compalzy, Niagara
Falls,
N. Y. (U.S.A.)
W. F. SHEELY
1 A. I3. MICHAEL AND F. J. HUEGEL, Acta Met., 5 (1957) 339. 2 M.L. POCHON,C.R.MCKINSEY, R. A. PERKINS AND W. D. FORGENG, RegionalConference on Reactive Metals, hn. Inst. Mech. Engrs., 1958. Received May 23rd, 1960 J. Less-Common
The ammonolysis of zirconium(W)
Metals. 2 (1960) 399-401
chloride
Tensimetric studies made by FOWLES AND POLLARD’ showed that one mole of ammonium chloride was formed in the reaction of zirconium(IV) chloride with ammonia at -63” and -36°C. However, although these experiments suggested the formation of the ammonobasic zirconium(IV) chloride ZrC13(NHz), xNH3, this compound was not isolated, and in comparable experiments with vanadium(IV) chloride213, where VC12(NH2)2, xNH3 was formed under tensimetric conditions, ammonolysis was found to be more extensive when ammonium chloride was removed from the reaction mixture by washing it with liquid ammonia; VCl(NH&, 2NH3 was isolated in this way. Removal of ammonium chloride from the products of the ammonolysis of zirconium(IV) chloride does not, however, effect a greater replacement of chlorine atoms, and the ammonobasic zirconium(IV) chloride predicted in the tensimetric experiments can be isolated in almost quantitative yield. The small amount of zirconium (7%) found in the soluble portion probably results from the formation of complex zirconium anions similar to those found in the titanium(IV) halide-ammonia systemsd. Such complex formation would be small and would occur only in concentrated solutions of ammonium chloride. More extensive ammonolysis may sometimes be effected by heating the ammonobasic metal chlorides in vacua and then re-treating with liquid ammonias, but this is not very effective with zirconium(IV) chloride because a second zirconium-chlorine bond is only partially ammonolysed even when the product is heated to 100’. After such a treatment, however, more zirconium is found in the soluble portion, and it may be that the heating helps to break down the polymeric solid so that it dissolves in the presence of ammonium chloride. The ammonia which is attached to the ammonobasic zirconium(IV) chloride is J. Less-Common Metals. 2 (1960) 401-403
SHORT COMMUNICATIONS
402
steadily lost when the compound is heated in vacua, and at 100' the product has the composition ZrCL(NH2), NH3. The thermal decomposition (cf. Table II) is in complete agreement with that of the mixture. It is of interest to note that although ammonia forces the solvolysis of only one zirconium-chlorine bond, methylamine goes a stage further, which contrasts with the behaviour of titanium(IV) chloride where ammoniac and methylamine’ solvolyse three and two titanium-chlorine bonds respectively. These results may be correlated with the effect of the size of the metal chloride on the relative base strengths of ammonia and methylamines. Thus ammonia may be more basic than methylamine when titanium(IV) chloride is the reference acid since the four groups bonded to titanium should cause an appreciable amount of steric hindrance to the attacking ammonia or amine molecule. Since the zirconium atom is larger than the titanium atom, this steric hindrance should be less with zirconium(IV) chloride, and methylamine will be a better electron donor than ammonia.
EXPERIMENTAL
Zirconium(IV) chloride was prepared by the action of dry chlorine on heated zirconium strip (Murex), and purified by sublimation. Found: 25, 39.3; Cl, 61.0.ZrC14 requires: Zr, 39.2; Cl, 60.8%. Analyses for zirconium, chlorine, and nitrogen, were carried out as described previouslys. Reaction of zivconium(IV) chloride with liquid ammonia The white flocculent solid initially formed was filtered from the colourless solution and washed six times with 50 ml of liquid ammonia. Both soluble and insoluble products were kept in vacua for 6 h before being analysed; the soluble portion, which clung tenaciously to the sides of the vessel, was hydrolysed irt situ (cf. Table I, run I). In other experiments (cf. Table I, runs 2,3, and 4), the products were heated ilz vacua for 2 h after the second and fourth washes, and kept irz vacua for 12 h after the final wash; the total soluble product was heated to 50” for 12 h before analysis.
TABLE
Temp. of pumping RUB No.
I
after and and 4th washes (“Cl
No pumping
Insoluble %Zr
Y’Ct
O/o N
I
Soluble product
Product Zr
:
Cl
30.4 34.3 28.2
1.00 : 2.90
:
N
zr
Soluble Zr
:
CL
:
N
Total ZY
: 6.04
I.00
:
17.1
:
17.5
0.07
:
IO.9
2
20
32.1 35.8 26.1
1.0"
: 2.87 : 5.30
I.00
: II.9
0.10
3
50
31.6 34.6 27.6
1.00
: 2.82
I.00 : IO.1 : 10.0
0.20
4
100
34.1 33.7 26.6
1.00
: 2.54 : 5.08
: 6.74 : 7.76
0.33
: 5.69
1.00
J. Less-Common
Metals, 2 (1960) 401-403
403
SHORT COMMUNICATIONS
Samples of the insoluble products ious periods (cf. Table II).
were heated
TABLE
in vacua at 50” and then 100’ for var-
II
INSOLUBLEPRODUCTS,THERMALDECOMPOSITION Temperature
RU?& NO.
(“C)
Time
IO0
50
Y(,Zr q!Jl O/ON Zr
:
Cl
:
N
YhZr "SC1y/oN
z,
x.00 : 2.92
Cl
:
N
I
I?.
37.3
43.0
16.6
1.00 : 2.96 : 2.90
39.6
2
24
39.2
43.5
13.9
1.00 : 2.86 : 2.31
40.1 44.1 13.3
1.00
: 2.83 : 2.16
3
6
: 2.88 : 3.24
39.6 43.3 14.0
1.00
: 2.83 : 2.30
4
12
41.1 40.4 14.0
1.00
: 2.53 : 2.22
34.6 38.7 21.7 ---
1.00
-
44.9
We are grateful to the Esso Petroleum Company for providing (J.E.D.), and Messrs. Murex for a gift of pure zirconium metal. 1 2 3 4 5 6 7 8 9
:
(h) II.9
a maintenance
: I.96
grant
G. W. A. FOWLES AND F. H. PoLLARD,J.C~~~.SOC., (1953) 4128. G. W. A. FOWLES AND D. NICHOLLS,J. Chem.Soc.,(1958) 1687. G. W. A. FOWLES AND D. NICHOLLS, unpublished observations. G. W. A. FOWLES AND D.NICHOLLS, J. Chem,Soc.,(Ig59)ggo. H. MOUREU AND C. H. HAMBLET,~. Am.Chem.Soc.,59 (1937) 33. G. W. A. FOWLES AND F. H. POLLARD,~. Chem.Soc., (1953) 2588. R.T.COWDELL AND G. W. A. FOWLES,J. Chem. Sot., (1960) 2522. H. C. BROWN, J. Am. Ghem. Sot., 67 (1945) 378. J. E. DRAKE AND G. W. A.FowLEs,J. Chem.Soc., (1960) 1498.
J. E. G. W.
A.
DRAKE FOWLES
Dept. of Chemistry, The University, Southamptolz (Great Britain) Received J,
.bS.S-COmmO?Z
ibfc?tUk,
August
Qh, 1960
2 (1960) 401-403