ZrONO3)2-H3PO4-KF(HF)-H 2O system at molar ratios of PO 4 3- /Zr = 0.5-1.6 as the basis for phase formation

Article abstract of DOI:10.1134/S0036023611010098

The system ZrO(NO₃)₂-H₃PO ₄-KF(HF)-H₂O was studied at 20°C along sections at molar ratios of PO ₄ ^3- = 0.5, 1.0, and 1.6; KF: Zr = 1-5; and HF: Zr = 2-6. Phases in precipitates were identified by X-ray powder diffraction; IR spectroscopy; and crystal-optical, chemical, X-ray fluorescence and thermal analyses. The following crystalline phases were isolated: potassium fluorozirconates K₃ZrF₇, K₂ZrF₆, δ-KZrF₅, and KZrF₅ ? H₂O; zirconium hydrophosphate Zr(HPO₄)₂ ? 0.5H₂O; and potassium fluorophosphate zirconate K₃Zr₃F ₃(HPO₄)₃(PO₄)₂. The following amorphous basic oxo(hydroxo)fluorohydrophosphate nitrates were isolated: K₄Zr₄O_2.5F₈(HPO ₄)₂(NO₃)₃ ? 6H₂O, K₂Zr₃O₃F₂(HPO₄) ₂(NO₃)₂ ? H₂O, and KZr ₃O_1.5F₃(HPO₄)₂(NO ₃)₃ ? 2H₂O. Fields of solid phases were constructed, and the roles of anions and cations in the phase formation were considered.

Full text of DOI:10.1134/S0036023611010098

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2011, Vol. 56, No. 1, pp. 11–17. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © M.M. Godneva, D.L. Motov, O.A. Zalkind, 2011, published in Zhurnal Neorganicheskoi Khimii, 2011, Vol. 56, No. 1, pp. 13–19.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
ZrO(NO3)2–H3PO4–KF(HF)–H2O System at Molar Ratios
of PO34–/Zr = 0.5–1.6 as the Basis
for Phase Formation
M. M. Godneva, D. L. Motov, and O. A. Zalkind
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Research Center, Russian
Academy of Sciences, Akademgorodok, 184209 Russia
Received March 27, 2009
Abstract—The system ZrO(NO3)2–H3PO4–KF(HF)–H2O was studied at ~20°C along sections at molar
ratios of PO34–/Zr = 0.5, 1.0, and 1.6; KF : Zr = 1–5; and HF : Zr = 2–6. Phases in precipitates were idenꢀ
tified by Xꢀray powder diffraction; IR spectroscopy; and crystalꢀoptical, chemical, Xꢀray fluorescence and
thermal analyses. The following crystalline phases were isolated: potassium fluorozirconates K3ZrF7,
K2ZrF6,
rophosphate zirconate K3Zr3F3(HPO4)3(PO4)2. The following amorphous basic oxo(hydroxo)fluorohydroꢀ
phosphate nitrates were isolated: K4Zr4O2.5F8(HPO4)2(NO3)3 6H2O, K2Zr3O3F2(HPO4)2(NO3)2 H2O,
and KZr3O1.5F3(HPO4)2(NO3)3 2H2O. Fields of solid phases were constructed, and the roles of anions and
δꢀKZrF5, and KZrF5 · H2O; zirconium hydrophosphate Zr(HPO4)2 · 0.5H2O; and potassium fluoꢀ
·
·
·
cations in the phase formation were considered.
DOI: 10.1134/S0036023611010098
3−
Phosphates of tetravalent elements have been well
studied and described by Tananaev et al. [1]. Fluoroꢀ
phosphates are a new class of compounds that is
unknown for Group IV elements. Representatives of
this class, each containing several acidic ligands, have
special properties. For example, a combination of two
luminogenic groups, F [2] and PO4 [3], each being
active in luminophores, in the same compound is of
significant interest because this should improve Xꢀray
luminescence properties of materials including these
groups.
Zr = 2–6,
= 0.5 and 1.6, and KF : Zr = 1–3.
PO4 Zr
2H2O was added to continuously stirred initial
ZrO(NO3)2 2H2O solutions in fluoroplastic beakers
KF
·
·
with cups.Once the mixtures became homogeneous in
several minutes, H3PO4 was added drop by drop. After
keeping the mixtures for seven days or more at room
temperature, precipitates were filtered off, washed
with cold water and with alcohol mixed with water,
and then dried in air.
Phases in the precipitates were identified by Xꢀray
powder diffraction; IR spectroscopy; and crystalꢀoptiꢀ
cal, chemical, and thermal analyses. The phosphate
ion was determined by reaction with ammonium
molybdate; zirconium ion, by trilonometry; potasꢀ
sium ion, by flame photometry; fluoride ion, by
potentiomety after double distillation of H2SiF6; and
Previously, we investigated a section of the
ZrO(NO3)2–H3PO4–KF–H2O system at molar ratios
3−
of
= 1.5–2.0. For the first time, we isolated
PO4 Zr
crystalline potassium fluorophosphate zirconate
K3Zr3F3(HPO4)3(PO4)2 and amorphous phosphate
nitrate, the formula of which had not been found [4].
−, by the Kjeldahl method. Phosphorus, zircoꢀ
NO3
nium, and potassium were also determined by Xꢀray
spectroscopy. The water content was found by thermoꢀ
gravimetry and isothermal drying at 250°С.
It is of interest to examine the formation of fluoroꢀ
phosphate zirconates over wide molar ratio ranges.
EXPERIMENTAL
RESULTS AND DISCUSSION
The initial substances used were ZrO(NO3)2
KF 2H2O, and 85% H3PO4 (all of pure for analysis
grade); and 36.4% HF (high purity grade). The
ZrO(NO3)2–H3PO4–KF(HF)–H2O system was studꢀ
ied along sections at molar ratios of HF : Zr = 0,
·2H2O,
Table 1 presents selected data on the compositions
of the initial mixtures and isolated precipitates, which
contain in some cases more than one phase, thereby
indicating a complex mechanism of equilibration in
the system. Figure 1 shows schematics of phase formaꢀ
·
PO34− Zr
= 0.5 and 1.0, and KF : Zr = 1–5 and HF : tion fields. The presence of a small amount of admixꢀ
11

12
GODNEVA et al.
Table 1. Formation of solid phases in sections of the ZrO(NO3)2–H3PO4–KF(HF)–H2O system
Precipitate composition
Initial
solution,
ZrO2 wt % (mol/mol)
Addition,
F : Zr
chemical composition, wt %
F–
mol/mol HF/Zr = 0,
phase
composition
PO34−
NO3−
K+
Zr(IV)
H2O
3−
= 0.5
PO4 Zr
4.9
5.0
1.0
2.1
5.3
1.0
2.1
3.1
1.0
4.2
18.7
11.3
25.3
9.9
37.4
30.5
34.4
34.7
15.9
29.0
37.7
–
14.8
10.7
16.5
4.5
19.9
2.5
12.4
–
5.2
10.0
–
VIb, II
VIb
15.0
16.7
27.6
4.7
5.7
VIa, I, II
VId, Va
VIc, V
II, V, IX
VIe, IXa
I, II
9.7
18.6
24.0
14.15
22.4
–
10.5
11.7
15.0
23.4
26.9
23.2
4.9
9.9
18.7
9.8
4.8
–
14.8
6.3
13.2
24.0
–
–
–
3−
mol/mol HF/Zr = 0,
= 1.0
PO4 Zr
2
5
7
2
2
2
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
VII
VII
VII
–
–
3−
mol/mol HF/Zr = 2–6,
= 0.5, K/Zr = 1
PO4 Zr
4.4
4.9
2.1
3.1
5.2
6.6
2.1
5.2
3.1
4.2
8.6
40.3
–
10.3
13.6
–
12.5
–
–
–
–
–
–
–
–
VI, IIa
IV, II, VI, VIII
IV
–
–
–
–
–
5.0
–
–
–
–
5.4
–
–
–
–
IV, II
10.0
10.6
15.8
16.2
11.8
–
27.3
–
11.4
–
22.0
–
15.3
VI, V, IX
IV
–
–
–
–
IV, VIII
III
–
–
–
–
3−
mol/mol HF/Zr = 2–6,
= 1.6, K/Zr = 1–3
PO4 Zr
4.6
4.9
9.3
5.0
2.11
4.22
3.11
4.23
13.9
29.6
–
6.8
–
51.5
–
–
–
–
–
–
–
VII
–
–
–
IV, VII
IV, VIII
IV, VII
–
–
–
–
–
–
–
Note: Phase notation: (I) K ZrF , (II) K ZrF , (III) δꢀKZrF , (IV) KZrF
⋅ H O, (V) phase x, (VIa) phase y, (VIb)
2
3
7
2
6
5
5
K Zr O F (HPO ) (NO ) ⋅ 6H O, (VIc) phase z, (VId) K Zr O F (HPO ) (NO ) · H O, (VIe) KZr O F (HPO ) (NO ) ⋅ 2H O,
4
4
2.5
8
4 2
3 3
2
2
3
3
2
4 2
3 2
2
3
1.5
3
4 2
3 3
2
1
2
3
(VII) K Zr F (HPO ) (PO ) , (VIII) Zr(HPO ) · 0.5H O [3, card 82ꢀ1422], and (IX) KNO . Molar ratios K : Zr are 1, 2, and 3.
Insignificant amount of a phase.
3
3
3
4 3
4 2
4 2
2
3
a
tures is not indicated. For example, the precipitates in At KF : Zr = 2–3, fluorozirconates are dominated by
the field of phases II and V contain K3ZrF7 and KNO3
admixture phases.
K2ZrF6, and at higher KF : Zr, by K3ZrF7.
3−
3−
At HF : Zr = 2–6, low
(0.5), and KF : Zr =
PO4 Zr
At HF : Zr = 0, low
, and low KF : Zr
PO4 Zr
1, as well as in the system without HF, fluorophosphate
phases V and VI form (Fig. 1b). The increasing HF : Zr
(mol/mol) ratio leads to the formation of phases IV
and VIII and then fluorozirconates (phases IV and
III); at low zirconium concentrations, however, amorꢀ
phous phase VI in a mixture with phases IV and VIII
dominates and also there is an admixture of K2ZrF6. At
(mol/mol), potassium fluorophosphate zirconates V
and VI form (Fig. 1a). At low zirconium concentration
(~5% ZrO2), in some cases cocrystallization of insigꢀ
nificant amounts of K2ZrF6 and K3ZrF7 is detected
along with the formation of amorphous potassium fluꢀ
orophosphate zirconate. With increasing KF : Zr
molar ratio, the content of fluorozirconates increases.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

ZrO(NO3)2–H3PO4–KF(HF)–H2O SYSTEM
13
(a)
KF/Zr, mol/mol
6
I, VIa
5
4
II, V
3
2
VIc, V
VIb
5
VId
VIe
1
10
15
20
ZrO , wt %
2
F/Zr, mol/mol
(b)
F/Zr, mol/mol (c)
II
6
6
5
III
5
4
IV
IV, VIII
4
V, IV, VIII
IV, VIII
3
3
2
1
IV, VII
2
VI, V
VII
VIc
5
VId
VIe
1
10
15
ZrO , wt %
5
10
ZrO , wt %
2
2
Fig. 1. Phase fields in the sections in the ZrO(NO ) –H PO –KF(HF)–H O system at molar ratios of (a) HF : Zr = 0 and
3 2
3
4
2
3−
3−
PO34− Zr
PO4 Zr
= 0.5; (b) HF : Zr = 2–6,
= 0.5, and KF : Zr = 1; and (c) HF : Zr = 2–6,
= 1.6, and KF : Zr = 1–3.
PO4 Zr
PO34− Zr
with phosphateꢀfree phases (Table 3). The IR specꢀ
trum suggests that phase V contains an H2PO4 group.
If it is assumed that all the NO3 groups belong to KNO3
and if the contents of phases II and IX in the compoꢀ
sition of the precipitate with phases V, II, and IX are
taken into account, then the suggested general forꢀ
= 1.5, at F : Zr < 3, as well as in the system
without HF, phase VII forms; and at F : Zr > 3, phases
IV and VIII form.
Phase V consisting of anisotropic uniaxial crystals
with negative extinction and refractive indices of Ng
=
1
1.524 and Np < 1.377 is isolated only in a mixture
with other phases. The Xꢀray diffraction pattern is preꢀ
sented for its mixture with amorphous phase VIc
(Table 2), and the IR spectrum is shown for its mixture
mula of phase V is K2ZrOFPO4
· H2O.
There are a number of Xꢀray amorphous phases for
which we found different refractive indices: = 1.514
N
(phase VIa), 1.549–1.555 (phase VIb), 1.565 (phase
VIc), and 1.590 (phases VId and VIe) at an accuracy of
1
The crystalꢀoptical data were obtained by M.P. Rys’kina.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

14
GODNEVA et al.
Table 2. Xꢀray diffraction data
determination of
N
0.003. All Xꢀray amorphous
phases in Fig. 1 are denoted by VI. Phase VIa is
detected at high KF : Zr (>5) only in combination with
fluorozirconates. The other phases are obtained at KF :
Zr = 1–2.
The IR spectrum of phase VIa exhibits diffuse
absorption in the range 959–1200 cm–1, which is indicꢀ
ative of the presence of phosphate groups (Table 3).
Bands of a nitrate component and oxo groups are
absent.
Product of thermolysis
of phase VIb at 480
Phase V
°
C
d
, Å
Irel
d
, Å
Irel
7.6
10
8
6.51
10
8
7.2
5.73
6.4
25
5
5.6
9
Phase VIb has the following composition:
For K4Zr4O2.5F8(HPO4)2(NO3)3 · 6H2O anal.
5.60
5.20
4.85
4.64
4.05
3.75
3.52
3.24
3.01
2.86
2.80
2.76
2.63
2.33
2.19
2.15
2.10
2.05
2.01
1.940
1.915
1.824
1.775
1.735
1.705
1.684
1.645
1.620
1.576
1.520
5.33
8
11
17
23
8
4.731
4.381
3.851
3.683
3.40
41
49
59
13
13
88
100
48
9
calcd., wt %: K+, 13.0; Zr(IV), 30.4; F–, 12.6; PO34–
15.8; NO–3 , 15.5; H2O, 9.0.
Found, wt %: K+, 11.3; Zr(IV), 30.5; F–, 10.7;
PO34– , 15.0; NO3– , 13.4; H2O, 10.0.
,
55
33
100
30
10
13
13
36
8
In the IR spectrum of phase VIb (Table 3, Fig. 3),
there is almost no sign of absorption in the range 400–
550 cm–1, which would be characteristic of terminal fluꢀ
orine atoms; however, there is absorption at 352 cm–1,
which can be attributed to bridging fluorine atoms [8].
In the DTA curve for phase VIb (Fig. 3), the lowꢀ
temperature endotherm is caused by water removal. Its
3.19213
2.951
2.85213
2.781
2.633
2.521
2.351
2.233
2.211
2.141
2.0713
2.0251
2.001
1.9771
1.9181
1.8401
1.6951
1.65413
1.4681
1.3231
diffuse shape (the peak extends to 273°С) suggests
19
32
9
that, along with removal of crystallization water, there
is oxolation of OH groups; that is, the initial phase
contains hydroxo groups. The second peak (at 406–
459
into KZr2(PO4)3, ZrO2, and, possibly, KZrOF3. The
third peak (at 655–694 ) is most likely to be due to
°С) is induced by the decomposition of the phase
7
°С
29
22
17
30
24
24
26
9
14
16
16
14
11
11
33
29
11
28
16
16
melting. Fluorine was shown [8] to be removed graduꢀ
ally without giving rise to peaks. The exotherm (at
338–352
amorphous phase. According to Xꢀray powder diffracꢀ
tion, the decomposition product at 690 comprises
°С) is caused by the recrystallization of the
°С
KZr2(PO4)3 and, possibly, K2Zr2O5. An approximate
schematic of the thermal decomposition of phase VIb
can be the following:
K4Zr4O2.5F HPO
NO ⋅ 6H2O
)
3
3
(
4 )2 (
8
76−146°C
⎯⎯⎯⎯⎯→K4Zr4O2.5F HPO
NO
)
3
3
(
4 )2 (
8
8
480°C
⎯⎯⎯⎯→KZr PO + KZrOF3 + ZrO2
(
)
2
4
3
7
+ amorphous phase
990°C
8
⎯⎯⎯⎯→KZr PO + ZrO2
(
)
2
4
3
9
+ amorphous phase
1250°C
17
12
10
15
⎯⎯⎯⎯→ZrO2 + amorphous phase.
Phase VIc is amorphous. It is found in a mixture
with crystalline phase V. The composition of phase VIc
is not found.
Phase VId precipitates as a gel, which, after drying,
becomes a glassy mass. Crystalꢀoptical analysis of this
phase detects an insignificant amount of KNO3, which
is hardly detectable by Xꢀray powder diffraction.
1
2
Note: Lines: ( ) KZr (PO ) [5, card 70ꢀ1905], ( ) ZrO [5, card
2
4 3
2
3
86ꢀ1451], and ( ) KZrOF [5, card 22ꢀ875]. The bold numꢀ
bers represent the lines of phases of unknown compositions.
3
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

ZrO(NO3)2–H3PO4–KF(HF)–H2O SYSTEM
15
Table 3. Wavenumbers (cm–1) of maxima of absorption bands in the IR spectra of phases
VI
а
, II, I
VIb
VId
–
VIe
II, V, IX
Assignment [6, 7]
470
–
b
w
b
475
–
b
450
–
450
510
560
–
ν
ν
(Zr–F)
(Zr–F)
500
–
b w
–
535
650
b
b
–
640
–
628
692
–
640
690 sh
–
ν4 (PO4)
–
685
840
–
–
ν2(NO3)
ν3(PO4)
1030
1035
1060
1220
1400
1570
1640
3480
3630
s
s
1028
1184
1220
1380
1570
1630
–
s
1025
s
1050
1180
–
s
1150 sh
sh
1195
1220
1380
1570
1650
3400
–
–
–
–
δ
(POH)
1400
–
ν3 (NO3)
δ
ν
(H–O–H)
(H2O)
1670
–
w
b
1660
3520
3600
b
–
n
–
Note: w, weak; s, strong; b, broad; n, narrow; sh, shoulder.
For K2Zr3O3F2(HPO4)2(NO3)2 · H2O anal. calcd., cursors in producing ionꢀexchange materials, glasses,
wt %: K+, 10.13; Zr(IV), 35.45; F–, 4.92; PO34– , 27.56; optical fibers, inorganic membranes, etc. These comꢀ
NO–3 , 16.07; H2O,O, 8.55.
−
pounds contain significant amounts of K+ and
NO3
Found, wt %: K+, 9.9; Zr(IV), 32.1; F–, 4.5; PO34–
,
ions. Moreover, potassium fluorophosphate zirconates
in some cases contain the phosphate group so that the
27.1; NO–3 , 18.6; H2O,O, 8.3.
Phase VIe is a slightly anisotropic substance with
undulose extinction.
PO34− Zr
molar ratios
in them (0.66 and 1.67) are
higher than those in the initial solutions (0.5 and 1.0),
respectively. Hydrates of basic zirconium orthophosꢀ
phates are known to have hydroxyl groups, which is
confirmed by the ability of these compounds to anion
exchange. Similarly, the presence of hydrophosphate
groups explains the ability to cation exchange. For
basic compounds, the number of hydroxyl groups is
larger than the number of HPO4 groups. It can be
assumed that the amorphous phase should be
For KZr3O1.5F3(HPO4)2(NO3)3 · 2H2O anal.
calcd., wt %: K+, 4.82; Zr(IV), 33.79; F–, 7.04; PO34–
23.51; NO–3 , 23.03; H2O, 4.46.
,
,
Found, wt %: K+, 4.8; Zr(IV), 36.6; F–, 6.3; PO34–
23.3; NO–3 , 22.4; H2O, 4.8.
For the KZr3O1.5F3(HPO4)2(NO3)3 · 2H2O phase
after water removal (<210 ), the weight loss to 420
is 16.81 wt %, which is 22.66% based on
− at a theꢀ
°С
°С
NO3
oretical content of 23.0%. The product of annealing to
420 mainly consists of KZr2(PO4)3 and also KZrOF3
and ZrO2.
The IR spectra of phases VIb, VId, and VIe contain
bands at 1220 cm–1, which are assigned to
(POH) [6,
2
Zr(OH)PO4 or Zr(OH)3(HPO4)0.5 in which a number
of OH groups is replaced by fluorine atoms, for examꢀ
ple, for the latter by the scheme
°С
Zr(OH)3(HPO4)0.5 (or Zr2(OH)6HPO4,
δ
HZr2(OH)7HPO4, H4Zr4(OH)14(PO4)2)
H4Zr4(OH)6F8 (PO4)2.
7]. These substances should probably be classified as
polymers containing hydroxyl and acid orthophosꢀ
−
phate groups [1]. Significant contents of
and F–
NO3
Some of the OH groups are replaced by nitrate
groups via anion exchange, and a proton of hydroꢀ
phosphate group is replaced by potassium via cation
exchange, which gives rise to a compound of complex
composition K4Zr4O2.5F8(HPO4)2(NO3)3. Similar conꢀ
siderations are also applicable to other basic phases.
In the ZrO2–H2SO4–KF–H2O system [8], fluoꢀ
rozirconates K2ZrF6 and K3ZrF7 form at high molar
ratios KF : Zr (≥6), which are close to stoichiometric
ions in the precipitates and the presence of bands in
the IR spectra in the ranges 1380–1400 cm–1 (attribꢀ
NO3−
3600 cm–1
uted to
) and 800–900 cm–1 (ZrO) and also at
ν(OH)) allow one to identify phases VIb,
(
VId, and VIe as oxo(hydroxo)fluorohydrophosphate
nitrate zirconates.
We can state that amorphous polymeric comꢀ
pounds form in the studied ranges of molar ratios of
formulaꢀforming components, these compounds by
analogy with basic phosphates [1] being useful as preꢀ
2
Hereafter, water molecules are omitted.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

16
GODNEVA et al.
1
2
3
4
5
3600
3200 2800 1700
1300
900 800
600
400
, cm–1
ν
Fig. 2. IR spectra: (
1
) mixture of phases V and II, (
2
) phase VIa, (
3
) phase VIb, (4) phase VId, and (5) phase VIe.
ratios in these compounds. In the studied system, increases to 6–7. Phosphate ions play their role in the
formation of fluorineꢀcontaining compounds also in
the presence of hydrofluoric acid (Figs. 1b, 1c). Fluoꢀ
rozirconate forms at lower molar ration F : Zr than
that in the absence of phosphate ions.
potassium hexaꢀ and heptafluorozirconates form even
at KF : Zr = 1, which can be explained by zirconium
redistribution between the amorphous potassium fluoꢀ
rophosphate zirconate and fluorozirconates phases.
Apparently, lowꢀsoluble zirconium phosphates iniꢀ
tially form. However, phosphate ions are insufficient
to bind all of the remaining zirconium, and the latter
reacts with fluorine and potassium ions, which are sufꢀ
ficient to form fluorozirconates. As a result, F : Zr
When the potassium ion content is low (KF : Zr = 1)
and part of the KF is replaced by HF, hexafluorozirꢀ
conate forms at a higher molar ratio F : Zr in the soluꢀ
tion than required by stoichiometry for the formation
of a solid phase (Fig. 1b). In the absence of HF, a domꢀ
inant role is seemingly played by anions, whereas in
the presence of HF, the role of the cation manifests
itself. At high F : Zr (> 4) and, correspondingly, high
H+ ion concentration, there is no phosphate phase,
probably, because of the competing action of fluorine
ions and the increased solubility of the phosphate
phase (Fig. 1b).
ΔT, °C
76
352
338
297
273
406
655
681
146
581
Comparison of the previously investigated section
3−
of the system at a molar ratio of
= 1.5–2.0 [4]
PO4 Zr
694
with the section studied in this work showed that an
3−
459
increase in
in the initial solution leads to the
PO4 Zr
devitrification of amorphous phases and a change in
composition toward the conversion of basic phases to
neutral ones and then to acidic salts. In this process,
coordination of NO3 groups does not occur, the fracꢀ
τ
, min
Fig. 3. DTA curve for phase VIb. Sample size: 0.26 g. Heatꢀ
ing rate: 9 K/min.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

ZrO(NO3)2–H3PO4–KF(HF)–H2O SYSTEM
17
tion of phosphate groups in the compound increases Properties and Design of Functional Materials Based
so that their content approximately corresponds to the on Them.”
3−
molar ratio
drated.
, and the compounds are dehyꢀ
PO4 Zr
REFERENCES
In summary, the title system can be partitioned into
three subsystems. At low F : Zr (<2.5), phases that
simultaneously contain fluorine and phosphate groups
form. At medium F : Zr (2.5–3.8), fluoride and phosꢀ
phate phases form independently of each other. At
high F : Zr (>3.8), the phosphate component of the
system is not detected and the system behaves as a
purely fluoride system, in which only fluorozirconate
phases form.
1. I. V. Tananaev, I. A. Rozanov, K. A. Avduevskaya, et al.,
Phosphates of Tetravalent Elements (Nauka, Moscow,
1972) [in Russian].
2. M. M. Godneva, D. L. Motov, N. N. Boroznovskaya,
and V. M. Klimkin, Zh. Neorg. Khim. 52 (5), 725
(2007) [Russ. J. Inorg. Chem. 52 (2), 661 (2007)].
3. Luminescent Materials and Chemicals. Catalog
(Cherkassy, 1983) [in Russian].
4. M. M. Godneva, D. L. Motov, and V. Ya. Kuznetsov,
Zh. Neorg. Khim. 53 (10), 1770 (2008) [Russ. J. Inorg.
Chem. 53 (10), 1654 (2008)].
5. The Powder Diffraction File (International Centre for
Diffraction Data).
6. A. V. Shtemenko, V. G. Stolyarenko, and K. V. Domaꢀ
sevich, Zh. Neorg. Khim. 51 (7), 1092 (2006) [Russ. J.
Inorg. Chem. 51 (7), 1014 (2006)].
Crystalline potassium fluorozirconates and previꢀ
ously unknown basic amorphous phases have been
isolated. In the system fields of solid phases have been
constructed and the roles of anions and cations in the
phase formation have been considered.
7. V. V. Pechkovskii, R. Ya. Mel’nikova, E. D. Dzyuba,
et al., The Atlas of the Infrared Spectra of Phosphates.
Orthophosphates (Nauka, Moscow, 1981) [in Russian].
8. M. M. Godneva and D. L. Motov, The Chemistry of the
Titanium Family: Sulphates, Fluorides, and Fluorosulꢀ
fates from Aqueous Media (Nauka, Moscow, 2006) [in
Russian].
ACKNOWLEDGMENTS
This work was supported by the Presidium of the
Russian Academy of Sciences’ Program “Developꢀ
ment of Methods for Producing Chemical Substances
and Creation of New Materials”: Subprogram “Tarꢀ
geted Synthesis of Inorganic Substances with Tailored
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011