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Hydrogen Fluoride Glasses.

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Table I . Composition or various hydiogen lluoride glacses
Glass
No.
Compounds (7) a n d (8) are distinguishable by their behavior in sulfuric acid: whereas (8) may be reprecipitated
unchanged from concentrated sulfuric acid, (7) is successively
changed into a dark-blue sulfate a n d a violet compound. All
0
the observations made so far suggest that the benzenoid
system (7) is converted into the energetically more favorable
quinonoid form (9).
Received, February 27th. 1964
[Z 679/501 IE]
Publication deferred until now a t the author's request
German version: Angew. Chem. 76, 436 (1964)
Metal
fluoride
[mole]:;
11F
[mole-
%I
I
MgF?
76
24
7
CaF?
81
19
3
SrFl
74
26
4
RaF!
67
33
5
PbF?
42
S8
6
YF,
64
36
7
LaF3
84
16
8
LaF,
67
33
9
AlFi
63
37
10
GaF,
57
43
II
BiF,
70
30
12
ZrF4
53
47
13
ThFt
45
5s
14
ThF.
I2
88
;lass
No.
Metal
fluoride
[mole-
15
MgFa
BaF?
LaF3
GaF3
ThF,
II
6
I1
27
6
16
LaFi
GaF3
31
31
17
GaFJ
ThF,
20
70
I8
MgFr
PbFL
35
35
19
MgF2
SrF:
BaF?
PbFz
I.aF3
BiFj
18
4
28
4
4
14
;<]
I
[nioleHF
44
Most of the hydrogen fluoride glasses are non-toxic.
Nearly all a r e moisture-resistant under normal conditions,
a n d many have been exposed t o boiling water for some
hours without showing the slightest chemical attack or loss
in weight.
T h e refractive index of some hydrogen fluoride glasses a n d
the relative dispersion are extremely low, e.g. n d < 1.27. T t e
glasses are transparent from 2000 A t o 5 except for a small
absorption band at 2.8 p. Their thermal expansion coefficients are rather high and can be controlled by changing the
composition. W e have succeeded in preparing strong leakproof seals between hydrogen fluoride glasses and magnesium,
aluminum, and several alloys of these metals.
...
[ I ] Brit. Pat. 698200 (Febr. 20th, 1951), Imperial Chemical
Indu;tries, inventors: R. .l. Fielden and D . G . Wilkinson; Chem.
Abstr. 48, 7 3 1 3 (1954).
[I]R. Shibafa, Technol. Rep. Tdhoku Imp. Univ. Sendai Japan,
7, 53 (1928); Chem. Zbl. 1928, I, 2619.
[3] K. Fries, W. Pense, and 0. Peeters, Ber. dtsch. chem. Ges. 61,
1398 (1928).
[4] K. J . Farrington and W. K. Warbwfon, Austral. J. Chem. 10,
502 (1957).
Received, February 28th, 1964
[Z 682/499 IE]
Publication deferred until now at the author's request.
German version: Angew. Cheni. 76, 343 (1964)
Reactions of Halides of Group IV Elements
with Trifluoroacetic Acid [l]
By Dr. P. Sartori and Dipl.-Chem. M. Weidenbruch
Institut fur Anorganische Chemie und Elektrocheniie
der Technischen Hochschule Aachen (Germany)
Hydrogen Fluoride Glasses
By Dr. J. Schroder
Philips Zentrallaboratorium G m b H ,
Laboratorium Aachen (Germany)
Stable glass phases have been found in many systems of
metal fluorides a n d hydrogen fluoride within extensive ranges
of concentration. W e have succeeded in preparing transparent
stable glasses from hydrogen fluoride and the following metal
fluorides, which may be added alone or in admixture in any
desired proportions (cf. Table 1): Fluorides of the metals of
the second and third main a n d auxiliary groups of the periodic
table, of the lanthanides and some actinides, as well as ZrF4,
HfF4, PbF2, and BiF3. All other solid metal fluorides can be
added t o these glasses in limited amounts. Large proportions
of phosphates can also be incorporated into the glasses. Pyroceramic materials may be obtained by addition of certain
transition metal fluorides or by heat treatment.
Compared with other compounds containing H F , the binding
farces of the H F in t h e glasses a r e remarkably strong,
probably owing t o the formation of very strong hydrogen
bonds. T h e glass phases are stable over large ranges of composition; mixtures of only one metal fluoride a n d less
than 20 mole-% H F give stable glasses with scarcely any
tendency towards devitrification o r cristallization.
376
Some trifluoroacetates, mainly of metals which form basic
oxides, have been prepared by F. Swcirts [ 2 ] a n d later by G .
H. Cndy [3]. W e obtained some new compounds by the
reaction of the tetrachlorides of G r o u p I V elements with
anhydrous trifluoroacetic acid (Table I).
Tabl: I, Preparation of trifluoroacetates.
Metal
chloride
Conditions
Yield
Product
[ ",.I1
I
Sic14
70 'C, 250 h
benzene
Si(OCOCFdI
water-clear liquid,
b.p. 25 "C/lO-3 mni
Tic14
70 "C, 250 h
homogeneous
phase
3 T i O ( 0 c 0 c F ~ ) r . ZC F J C O O H
white crystals
ZrCla
40 "C, 4 h
heterogeneous
phase
Zr(0COCFj)J
white crystals
I00
ThCId
70 'C, 24 h
heterogeneous
phase
Th(OCOCF3)1
white crystals
100
I00
~~
Aizyew. Clrein. internot. Edit.
V d . 3 (1964) / No. 5
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