Journal of Minerals & Materials Characterization & Engineering, Vol. 8, No.1, pp 37-45, 2009
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37
Growth and Characterization Studies of SrCaMHP Single Crystal in
Silica Gel Medium and Laser Induced
Nucleation Reduction Strategy
G. Kanchana, P. Sundaramoorthi*, and G.P. Jeyanthi
Department of Bio-chemistry, Avinashilingam Deemed University, Coimbatore, TamilNadu,
India.
*Department of Physics, A.A Govt. Arts College, Namakkal, India-637001.
(Ph.No.-04286-266313 (off.) Fax- 04286-266323 , MailID-moorthi.sundara@gmail,com)
ABSTRACT
SrCaMHP (Strontium Calcium Magnesium Hydrogen Phosphate) crystals were grown in
silica gel medium using different gel densities, various concentrations of phosphoric acid
and supernatant solutions. The gel pH plays an im portant role in the formation of different
HPO4 species in the phosphoric system. The growth of SrCaMHP crystals depends upon
the pH of the inner reactant ionic concentration. The characterizations of grown crystals
were studied by FTIR, TGA/DTA, SEM, XRD and etching. The results are reported and
discussed in detailed manner.
Key words: SrCaMHP, SEM, laser light, calculi, surface m orphology, growth parameters,
trace elements, isotop es .
1. INTRODUCTION
SHP (Strontium hydrogen phosphate) and BHP (Barium hydrogen phosphate) were
grown in silica gel medium at room temperature and reported [1, 2]. The next approach is
to grow mixed crystal in silica gel medium at different environments, which contains two
major elements (Calcium, Phosphate), one minor or trace element (Strontium) and one
inhibitor (Magnesium). SrCaMHP is a mixed crystal, which typically represent the
biological crystals formed in the human urinary tracts called renal stones. Strontium (Sr) is
a silvery-white alkaline earth metal that exists in several stables (e.g. Sr-89, Sr-88) and
several radioactive (e.g. Sr-89, Sr-90) isotopes. Strontium is in the fifteenth most abundant
element in nature and it is the most abundant trace element in seawater. Thus it can
become incorporated in to all plants and animal tissues. The daily intake of strontium

38 G. Kanchana, P. Sundaramoorthi, and G.P. Jeyanthi Vol.8, No.1
varies from about 2.8 to 4.0 milligram/day. Of this a negligible quantity is supplied by air,
approximately 89 percent by food and the remaining 10 to 31 percent by water. Authors
have done a series of experiments with silica gel crystal growth medium at different pH
values ranging from 5.5 to 9 and have proved that one can obtain the periodic
precipitations, Liesegang rings [3-5] of biological crystals named as HAP, Brushite,
struvite , BMHP and SrMHP etc.
Strontium is present naturally in many foods for example spices, seafood, cereals,
grains, leafs and vegetables. There are some evidences that strontium is essential for
growth of animals, especially for the calcification of bone and teeth. Metabolism of
strontium closely resembles that of calcium, especially with regard to bone. The
absorption of strontium varies normally from 10 to 35 percent in injected dose. A 75 kg
standard man contains nearly 330 mg of strontium. The skeleton contains more than 98
percent of the strontium. The rest is distributed among soft tissues; the largest
concentration resides in the aorta, larynx, trachea and lower gastrointestinal tract. When
administrated orally, it is primarily excreted in the faces. Strontium is a low excreted the
sweat and in the milk of lactating females. If the mineral level of the body fluid increases,
automatic mineral deposition starts.
2. MATERIALS AND METHODS
The dissociation of phosphoric acid system can be represented by three-dissociation
equilibrium and the presence of various ions at various pH values are reported [6]. On the
account of these results, the gel pH in the range from 6 to 10 has been used (Milwaukee QS-
MN pH-600, packet digital pH-meter are used for measurements) in which the HPO42- ions
dominate or alone exist. This decreases the possibility of SrCaMP crystals occurring during
the SrCaMHP growth. The crystallization apparatus employed were glass test tube of 25 mm
diameter and 150 mm length for single diffusion method (SDP) and. thick walled 30 mm
diameter and 180mm long glass U tubes for double diffusion (DDP) method. The chemicals
used were Excelar-Qualigens AR grade SrCl2, CaCl2 and Mg (NO3) 2.2H2O (MW-258.41)
and E-Q AR grade phosphoric acid (Sp.gr.1.75). The SMS gel or water glass was prepared as
per the literature [7]. One of the reactant phosphoric acid was mixed with silica gel at desired
gel density and elevated temperatures. After the gel set, the supernatant mixture (Strontium
chloride+Calcium chloride+Magnesium nitrate) at a required mole solution was slowly added
along the walls of the growth columns (test tubes, U-tubes) over the set gels and tightly
closed to prevent evaporation. The growth parameters of SrCaMHP crystals in SDP, DDP are
presented in Table1 and Table 2 respectively. The optimum growth parameters are indicated
in bold letters. The growth columns, harvested crystals and different environments growth
are shown in Fig.1-7 then the growth systems were allowed to react within the gel medium
and the following chemical reaction takes place.
(SrCl2+CaCl2+Mg (NO3)2 .2H2O)+HPO4+Set gelÆSrCaMgHPO4+By products --- (1)

Vol.8, No.1 Growth and Characterization Studies of SrCaMHP 39
Table-1 Growth parameters of SrCaMHP crystals in SDP growth process.
Gel
density
gm /cc
Phosphoric
acid
concentration
(Inner reactant
mixed with
gel) N
Gel+
HPO4
pH
value
Gel setting
time
hrs
Supernatant
Concentration
(CaCl2+SrCl2)+
Mg ((NO3)2.
2H2O) (M)
Nucleation
observed in
hrs
Growth
period
in days
Growth
appearances
Inside the
growth
medium
1.03
1 1
1
1
6.4
6.8
6.9
7.3
26
16
1.
18
1:1:1
-do-
-do-
-do-
16
17
32
89 196 GTC,PC
1.03 1.5
1.5
1.5
1.5
6.6
6.9
7.1
8.0
28
1
3
46
-do-
-do-
-do-
-do-
26
16
46
66
190
GTC
1.04
1
1
1
1
6.3
6.8
6.9
7.4
34
6
1
68
-do-
-do-
-do-
-do-
12
22
28
68
140
GTC,PC
1.04 2
2
2
2
6.6
6.9
7.1
7.5
24
1
12
48
-do-
-do-
-do-
-do-
13
10
24
72
175 GTC
GTC-good transparent single crystals are observed.
PC-Poly crystals are observed.
Table-2 Growth parameters of SrCaMHP crystals in DDP growth process.
Gel
density
gm /cc
Phosphoric
acid
concentration
(Inner reactant
mixed with
gel) N
Gel+
HPO4
pH
value
Gel setting
time
Supernatant
Concentration
CaCl2+SrCl2+
Mg ((NO3)2.
2H2O) (M)
Nucleation
observed in
hrs
Growth
period
in days
Growth
appearances
1.03 1
1
1
1
6.0
6.5
6.9
7.1
48
16
1
26
2:2:2
-do-
-do-
-do-
45
26
22
90
140
GTC
1.03 2
2
2
2
6.4
6.9
7.2
8.1
36
4
1
98
-do-
-do-
-do-
-do-
20
22
86
98
170 GTC,PC
1.04 1
1
1
1
6.2
6.8
7.2
7.6
46
5
3
28
-do-
-do-
-do-
-do-
40
22
64
88
110
GTC
1.04 2
2
2
2
6.2
6.9
7.5
7.9
88
1
10
58
-do-
-do-
-do-
-do-
20
10
32
82
170
GTC,PC
GTC-good transparent single crystals are observed.
PC-Poly crystals are observed.

40 G. Kanchana, P. Sundaramoorthi, and G.P. Jeyanthi Vol.8, No.1
Fig-1 Fig-2 Fig-3 Fig-4
Fig-1 Growth of SrCaMHP crystals in SDP within laboratory environment
Fig-2 Growth of SrCaMHP crystals in SDP within laboratory environment
Fig-3 Growth of SrCaMHP crystals SDP with the sun light exposed medium
Fig-4 Growth of SrCaMHP crystals in DDP within the laboratory medium.
Fig-5 Fig-6 Fig-7
Fig-5 Growth of SrCaMHP crystal with laser exposed medium in DDP
Fig-6 Harvested SrCaMHP crystal in SDP
Fig-7 Harvested SrCaMHP crystal in DDP
3. CRYSTAL ANALYSIS (Characterization studies)
3.1 FTIR spectral analysis of SrCaMHP crystal
FTIR Spectrometer having KBr pellets sample holder and KBr detector was used for
the analysis. The KBr pellet samples were used and the absorption frequencies range from
600 to 4000cm-1. Fig 8 shows the FTIR spectrum of SrCaMHP crystals. The results match
with the reported values [8]. The absorption bonds, absorption frequencies of phosphate
group, hydroxyl group in plane and out of plane are analyzed and percentages of
transmittance were compared with the reported values. The values are tabulated in Table 3.
The functional group frequencies values confirm the SrCaMHP crystal constituents.

Vol.8, No.1 Growth and Characterization Studies of SrCaMHP 41
Fig-8, FTIR spectrum of SrCaMHP crystal.
Table-3, FTIR Spectral analysis of SrCaMHP crystal
SNO Composition/Bond Absorption
frequency
Reported value
cm-1
Absorption
frequency
observed values
cm-1
%
Transmittance
1.
Sr, Ca and Mg &hydrogen
O -H Symmetric, asymmetric.
(in plane)
3477 to 3207 2801
3555
3490
3318
33
20
18
21
2.
O-H out of plane
745 792 43
3.
PO4 group
1000 to 1100 1134
1055
988
15
15
35
4.
Ca, Sr and Mg / Appetite group
600-1010 (high
Frequency)
526
577
1066
22
32
15
3.2. Thermo gravimetric (TGA and DTA) analysis of SrCaMHP crystal.
The TGA and DTA of SrCaMHP crystals were carried out by STA 11500-PLTS
instruments. The SrCaMHP crystal of 2.439mg sample was taken to the TGA process. The
TGA was started from room temperature to 10000 C by heating at a constant rate. Fig.8
shows the TGA&DTA graph of SrCaMHP crystals. The % of weights present in the
SrCaMHP sample at a particular temperature was tabulated in Table 4 [10].

42 G. Kanchana, P. Sundaramoorthi, and G.P. Jeyanthi Vol.8, No.1
Fig.9. Thermo gravimetric (TGA and DTA) analysis of SrCaMHP crystals.
Table-4. Thermal Analysis of SrCaMHP crystals.
Points TGA DTA in
0C
Temperature (º
C)
% of SrCaMHP crystal
present
1
2
3
4
5
35
114
179
410
850
100
102
77
72
72
114.81
160.60
231.45
672.51
691.53
The TGA of SrCaMHP crystals were anhydrous up to 114 0C. Here after the remaining
sample is stable up to the end of the analysis.
The expected chemical reactions are:
SrCaMgHPO4.XH2O ▲ SrCaMgPO4 + X H2O -Heating up to 114 0C ---(2)
2SrCaMgPO4 ▲ 2 Sr Ca Mg +2PO4 -Heating up to 900 0C----(3)
Sr, Ca and Mg, are stable compounds with respect to the melting points. Twenty-two

Vol.8, No.1 Growth and Characterization Studies of SrCaMHP 43
percentages of SrCaMHP crystals were decomposed and 72% of the sample is stable.
3.3. Etching study of SrCaMHP crystal
A well-grown SrCaMHP crystal was immersed in HCl solution at a desired
concentration. The dissolution of SrCaMHP crystal depends upon the etchant concentration,
temperature, crystal morphology, etching time etc. [13-16]. The etch pits are shown in Fig.
10. The etch pits observed include helical pits, spiral pits, cone pit, leaf pit and step pits.
.
Fig-10. Chemical etching of SrCaMHP crystal at room temperature (300 Celsius). 1N HCl
etchant, 6 minutes etching time.
3.4. Scanning Electron Microscopy Study of SrCaMHP Crystals
A well-grown SrCaMHP single crystal was selected for the investigation of surface
morphology by using SEM. The SEM photograph was made in the version S-300-I
instrument. The sample named VCA-600 was kept in lobe middle; the data size was 640x480.
The minor and major magnifications of SEM were about 250 times. SEM acceleration
voltage was 25000 volts and the sample was kept in a high vacuum. 18200-micrometer
working distance and monochromatic color mode were employed. 200μm focusing of
SrCaMHP crystal SEM is shown in Fig. 11. In the surface analysis of SEM-SrCaMHP
crystal, few smooth surfaces, many fine grain boundaries and some valley regions are
observed [17-20].

44 G. Kanchana, P. Sundaramoorthi, and G.P. Jeyanthi Vol.8, No.1
Fig-11.SEM picture of SrCaMHP crystal
3.5. X-ray Diffraction of SrCaMHP Crystal
The XRD results revealed the crystalline property of crystal. The XRD pattern and
diffraction indices of the SrCaMHP crystals were recorded. Using the programme (Proszki)
the lattice parameters of the SrCaMHP crystal were calculated. The lattice parameters are
a=10.03Å, b=10.21Å, c=10.58Å, α=90.20˚, β= 90.02˚, γ=90.08˚. The volume of the unit cell
of the SrCaMHP crystal is 1083.46 (Ao)3. From this data, one can identified and confirmed
the SrCaMHP crystal system is triclinic [21-23].
4. CONCLUSION
The crystal structure, growth morphology, chemical constituents, surface morphology
and TGA/DTA analysis of strontium calcium hydrogen phosphate (SrCaMHP) crystals have
been investigated. The SrCaMHP crystals are grown in three different growth faces under
various growth conditions. Among them, the laser exposed growth medium is observed to
show better nucleation reduction and no crystals were formed, because of the inability to
attain super saturation. In sun light exposed medium partial nucleation are observed, since
average sunlight exposures to the growth medium are only eight hours per day. FTIR
spectrum is recorded and the functional group frequencies of SrCaMHP crystal are analyzed,
which confirm the SrCaMHP chemical constituents. Chemical etching studies are carried out
at room temperature. The etch pits and the crystal defects are noted. SEM studies identified
the surface morphology of grown crystal. The decomposition temperature, percentage of loss
of grown crystals is recorded in TGA/DTA analysis. Single crystal XRD data gives the
SrCaMHP crystal system with a triclinic structure.
SEM Picture ofSrCaMHPCr
ystal
-
100
µm

Vol.8, No.1 Growth and Characterization Studies of SrCaMHP 45
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