Journal of Minerals & Materials Characterization & Engineering, Vol. 9, No.2, pp.115-122, 2010
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115
In-vitro Studies of Biologically Important Barium Strontium Chromium
Magnesium Hydrogen Phosphate (BaSrCrMgHPO4) Mixed Crystal Growth
in SMS Gel Medium at Ambient Temperature and Its Characterization
Studies
J. Kishore Kumar, P. Ramesh, P. Suresh and P. Sundaramoorthi*
Department of Physics, Thiruvalluvar Govt. Arts College, Rasipuram, Namakkal, India-637401
*Corresponding Author: [e-mail], Ph-04287-252785, Cell-9486902430)
ABSTRACT
Kidney stone consists of various compounds. Mineral oxalate monohydrate and di-hydrate are
the main constituen t of kidn e y ston e s. However, the formation of calc ium oxalate kid n ey stones is
still not clearly understood. In this field of studies, several new hypotheses are created, which
includes nucleation, reduction of nucleation, crystal growth and or aggregation of formation of
different crystals such as oxalate monohydrate and oxalate di-hydrate. The effect of some
urinary species such as ammonium oxalate, calcium, citrate, proteins and trace elements were
reported by the author. The kidney stone constituents along with trace minerals are grown in
silica gel medium (SMS) which provides the necessary growth simulation (in-vivo). In the
artificial urinary stone growth process, growth parameters within the different chemical
environments were carried out and reported for several urinary crystals such as CaHP, SrHP,
SrMHP, BaHP, BaMHP and MgHP. In the present investigation, BaSrCrMHP (Barium
Strontium Chromium Magnesium Hydrogen Phosphate) crystals are grown in different growth
faces to attain the total nucleation reduction. Extension of this investigation, many
characterization studies have been carried out and compared with reported results.
1. INTRODUCTION
SrHP (Strontium hydrogen phosphate), CaHP (Calcium hydrogen phosphate) and BaHP (Barium
hydrogen phosphate) were grown in silica gel medium at room temperature. The next approach
is to investigate and grow mixed crystal in silica gel medium at different environments, which
contains one major elements (phosphate), three minor or trace elements (strontium, barium and
chromium) and one inhibitor (Magnesium). BaSrCrMHP is a mixed crystal, which typically
represents the biological crystals formed in the human urinary tracts called renal stones [1-3].

116 J. Kishore Kumar, P. Ramesh, P. Suresh and P. Sundaramoorthi Vol.9, No.2
2. MATERIALS AND METHODS
The silica gel, also known as SMS (Sodium meta silicate) was used in the present work as the
growth medium. The commercial water glass was added with double distilled water in 1:1 ratio
and mixed well. The container was left undisturbed for few days to allow sedimentation. Then
the solution was filtered and stored in a glass container and this solution is called stock solution.
The stock solution with density of 1.06g/cc was prepared. In the present work, analytical grade
reagents and double distilled water was used. The gel density used in the experiment ranges
from 1.06 g/cc to 1.03 g/cc [4-6]. Simple test tubes of 2.5 mm diameter and 15 cm length are
used. The concentration of phosphoric acid used in this work includes 0.5N, 1N, 1.5N and 2N
and the concentration of supernatant solutions [Strontium chloride (SC), Barium chloride (BC),
Chromium chloride (CC) and Magnesium chloride (MC)] varied from 0.5M to 2M. One of the
reactant – phosphoric acid was mixed within the gel solution and then it was poured about two-
third of the single test tubes. After the gel set, the supernatant solutions of
(BaCl2+SrCl2+Crcl2+MgCl2) were added slowly along the sides of the test tubes. The
supernatant solution diffuses through the set gel, which reacts with phosphoric acid present in the
gel leading to the growth of BaSrCrMgHPO4 single crystals. The chemical reaction takes place
as given below.
[BaCl2+SrCl2+CrCl2+MgCl2] +HPO42- → BaSrCrMgHPO4 + by product
Table 1. BaSrCaMHP crystal growth parameters and crystal morphology (SDP).
Gel density
gm /cc
Phosphoric
acid
concentration
in N
Gel +
H3PO4
pH valu
e
Gel setting
time
in hrs
Supernatant
concentration
BC, CC, SC and
MC, (M)
Nucleation
observed
in hrs
Growth
period in
days
Types of
crystal
observed
1.03
1
6.5
6.7
6.9
7.2
24
6
1
24
1:1:1
-do-
-do-
-do-
10
16
24
96
260 Needle lik
e
crystals
Dendrite
crystals
Platelet
crystals
Leaf like
crystals
Single
crystals
2
6.5
6.8
7.0
8.2
24
2
1
48
-do-
-do-
-do-
-do-
8
24
36
48
290
1.04
1
6.4
6.7
6.9
7.3
24
5
1
48
-do-
-do-
-do-
-do-
10
12
24
48
265
2
6.5
6.8
7.0
7.3
24
1
12
48
-do-
-do-
-do-
-do-
3
10
24
72
375

Vol.9, No.2 In-vitro Studies of Biologically Important BaSrCrMgHPO4 117
Figure 1. Growth of BaSrCrMHP medium with in laboratory (Gel density-1.04 g/cc).
Figure 2. Harvested BaSrCrMHP crystal.
3. RESULT AND DISCUSSION
The BaSrCrMgHPO4 crystals are grown in three different growth faces by applying various
growth parameters. Table 1 gives the growth parameters of BaSrCrMgHPO4 crystals and the
bold letters shows the optimum growth parameters. Among them, the laser exposed growth
medium shows better nucleation reduction and no crystals were formed, because of the inability
to attain super saturation. In the sun light exposed medium partial nucleation was observed, since
exposure of sunlight to the growth medium was only in day time that is six hours per day and the
growth period was ten months.

118 J. Kishore Kumar, P. Ramesh, P. Suresh and P. Sundaramoorthi Vol.9, No.2
4. CHARACTERIZATION OF BaSrCrMHP CRYSTALS
4.1 FTIR Spectral Analysis of BaSrCrMHP Crystals
FTIR Spectrometer having KBr pellets sample holder and KBr detector was used for the
analysis. The KBr pellet samples are used and the absorption frequencies range from 600 to
4000cm-1. Figure 3 shows the FTIR spectrum of BaSrCrMHP crystal. The absorption bonds,
absorption frequencies and percentage of transmittance was measured and compared with the
reported values [7-8]. The values are tabulated in Table 2 and it confirms the presence of
BaSrCaMHP crystal constituents.
Figure 3. FTIR Spectral studies of BaSrCrMHP crystals.
Table 2. FTIR Spectral studies of BaSrCrMHP crystal.
S.No. Composition/Bond
Absorption
frequency
Reported value
cm-1
Absorption
frequency
Observed values
cm-1
% of
Transmittance
1. Barium, Strontium, Chromiu
m
hydrogen
O-H Symmetric,
asymmetric (in plane)
3477 to 340
7
3801
3555
3490
3318
33
20
18
21
2. O-H out of plane 745 792 43
3. PO4 group
1000 to 110
0
1134
1066
988
15
15
35
4. Magnesium/Apatite
group
600-
1010 (high
frequency)
577
526
1066
32
22
15

Vol.9, No.2 In-vitro Studies of Biologically Important BaSrCrMgHPO4 119
4.2 Thermogravimetric Analysis of BaSrCrMHP Crystals
The TGA/DTA experiment simply measures the change in weight of a sample as a function of its
temperature. A plot of weight % as a function of temperature (T) can relate the weight change to
the stochiometry. In the present study, TGA is carried out for BaSrCrMgHPO4 crystal using
STA 1500 instrument in air atmosphere. The TGA and DTA of BaSrCaMHP crystals were
carried out by STA 11500-PLTS instruments. Powdered sample of BaSrCrMHP crystal of 6.68
mg was used for analysis in TGA. The temperature ranges from room temperature to 900oC by
heating at a constant rate. Fig-4. Shows the TGA and DTA graph of BaSrCrMHP crystals and
the percentage of weights are tabulated in Table 3 from TGA curve, it is obvious that the sample
becomes anhydrous beyond 100oC and 65.8% of the sample remains stable at 900oC. Barium,
Strontium, Chromium and Magnesium are stable up to 1130oC (melting point) and the expected
chemical reactions are
BaSrCrMgHPO4 . 2H2O Δ BaSrCrMgPO4 + 2H2O ↑
2BaSrCrMgPO4 2BaSrCrMg + 2PO2 ↑ + 2
3O2 ↑
Figure 4. TGA Studies of BaSrCrMHP Crystal.
Δ
Δ

120 J. Kishore Kumar, P. Ramesh, P. Suresh and P. Sundaramoorthi Vol.9, No.2
Table 3. Thermal Analysis of BaSrCrMHP crystals.
Critical
Points
TGA DTA in 0C
Temperature
(º C)
% of BaSrCrMHP
crystal present
1
2
3
4
5
35
122.19
190.69
480
800
100
104.4
78.8
65.8
65.8
122.94
170.33
237.58
668.33
686.87
4.3 Scanning Electron Microscopic Study of BaSrCrMHP Crystal
It is the best known and most widely used surface analytical techniques. SEM, accompanied by
X-ray analysis, is considered a relatively rapid, inexpensive, and non-destructive approach to
crystal surface analysis. It is often used to survey the surface analytical problems before
proceeding to the techniques that are more surface sensitive and more specialized. A well-grown
BaSrCrMHP 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 kept in lobe middle; the data size was 640 x 480 micro meter. The minor and major
magnification of SEM was 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 was employed. 200 μm focusing of BaSrCrMHP crystal SEM is shown in Figure 5.
In the surface analysis of SEM-BaSrCrMHP crystal, few smooth surfaces, many fine grain
boundaries and some valley regions were observed [9-10].
Figure 5. SEM photo of BaSrCrMHP crystal.

Vol.9, No.2 In-vitro Studies of Biologically Important BaSrCrMgHPO4 121
4.6 Single Crystal X-ray Diffraction
X-ray crystallography is one of the most useful methods for exploring the nature of matter. X-
ray diffractometry is used to determine the phase content in many minerals and materials. As a
result, it is used by researchers in a wide range of disciplines. It is used as an adjunct to chemical
analysis in the identification of the constituents of mixtures of crystalline phases, such as
minerals, cements and alloys; for measurements of the lattice parameters of artificially produced
structures such as to identify changes in raw materials or methods that might alter a drugs
efficacy. X-ray diffractory meter readings got from RSIC – IIT Chennai-25 in the BaSrCrMHP
single powder crystals. The XRD pattern and diffraction indices of the grown crystal are
calculated by Treor programme according to the values of 2θ in XRD [11-12]. The unit cell
parameters are shown in Table 4.
Table 4. Unit cell parameters of BaSrCrMHP.
From the data it is confirmed that the crystal system is triclinic.
4.7 Etching Study of BaSrCrMgHPO4 Crystal
A well-grown BaSrCrMHP crystal was immersed in HCl solution at a desired concentration.
The dissolution of BaSrCrMHP crystal depends upon the etchant concentration, temperature,
crystal morphology, etching time etc [13-14]. The etch pits are shown in Figure 6. The etch pits
were observed as plane pit, leaf pit and step pits.
Figure 6. Etch picture – (Etching time-7 minutes, 2N -HCl as an etchant).
Primitives in Å Interfacial angle in degree
a-10.013
α
=90.08
b-10.216
β
=90.02
c-10.684
γ=90.00
a≠b≠c
α
≠
β
≠
γ

122 J. Kishore Kumar, P. Ramesh, P. Suresh and P. Sundaramoorthi Vol.9, No.2
5. CONCLUSION
In the present work good transparent Barium Strontium Chromium Magnesium hydrogen
phosphate (BaSrCrMHP) single crystals were grown with well developed faces. Different growth
habits were observed with respect to the different pH values for gel density 1.03g/cc to 1.06g/cc.
The effect of sunlight and laser on the growth of BaSrCrMHP crystals were studied and found
that laser exposed medium produces better nucleation reduction. Characterization studies like
XRD, .FTIR, TGA/DTA, SEM and etching were done and the results analyzed. Using XRD
results, the grown crystal cell parameters are calculated and found the crystal system as triclinic.
The chemical components present in the grown crystals were confirmed by FTIR. Using
TGA/DTA graph, calculated the percentage of decomposition of grown crystals. The surface
morphology of the grown crystal was studied by SEM. The study of chemical etching was
carried out to obtain the etch pits pattern which gives the surface nature of grown crystals.
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