Synthesis and Characterization of the Double Perovskite Y2MgRuO6

Sahana Rößler; Ulrich Burkhardt; Liu H. Tjeng; Alexander C. Komarek

doi:10.3390/cryst13091365

,

and

Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany

^*

Author to whom correspondence should be addressed.

Crystals2023, 13(9), 1365;https://doi.org/10.3390/cryst13091365

Version Notes

Order Reprints

Abstract

A new double perovskite compound with nominal composition Y

_{2}

MgRuO

_{6}

is synthesized by the floating zone technique. X-ray diffraction measurements reveal a monoclinic crystal structure with space group

P 2_{1} / n

and monoclinic angle

β

= 90.178(1)

^{\circ}

as crystallographically expected for a double perovskite. A composition of Y

_{1.880 (8)}

Mg

_{0.953 (4)}

Ru

_{1.047 (4)}

O

_{6 - δ}

is revealed by our single crystal X-ray diffraction measurement. The magnetic susceptibility of this compound does not show indications of magnetic ordering down to the lowest temperature. A Curie–Weiss fit for the paramagnetic part above 300 K yields an effective moment that indicates an S = 1 Ru

^{4 +}

state. We attribute the occurrence of the S = 1 state and the lack of magnetic order to the presence of the

B / B^{'}

-site disorder.

Keywords:

floating zone method; double perovskite; ruthenate; crystal structure; magnetization

1. Introduction

Ru

^{4 +}

materials with a 4d

^{4}

configuration have recently attracted considerable interest due to theoretical models that propose unconventional magnetism arising from an interplay of spin–orbit coupling (SOC), superexchange and electron correlations [1,2,3]. Large crystal field and SOC in these materials might lead to a J = 0 ground state, which is expected to show only temperature-independent Van Vleck-type magnetism. In cubic K

_{2}

RuCl

_{6}

, the J = 0 ground state has been observed, indicating the unquenched orbital angular momentum in this compound [4]. In this type of material, the superexchange energy scale is comparable to the SOC, and therefore excitations between the J = 0 ground state and J = 1 triplon excited states are possible [5]. And new interesting magnetic ground states might appear in these materials [1,2,3,5,6,7]. Several Ru

^{4 +}

systems have been already studied in the past [8,9,10,11,12,13].

Compounds with a double perovskite structure are interesting because a face-centered cubic structure could induce bond-dependent frustration in spin–orbit coupled excitonic states [5,14]. In order to investigate the magnetic properties related to isolated Ru

^{4 +}

ions in the perovskite structure, a B-site ordered structure with Ru as the only magnetic ion is necessary. Several Ru

^{4 +}

double perovskite compounds have been already synthesized [15]. For La

_{2} M

RuO

_{6}

(with the

M^{2 +}

-ions Mg

^{2 +}

, Co

^{2 +}

, Ni

^{2 +}

and Zn

^{2 +}

), a double perovskite structure has been found [15,16,17]. (B-site ordering depends on the synthesis conditions [15,18,19]). For La

_{2}

MgRuO

_{6}

, the effective paramagnetic moment

μ_{p}

was found to be somewhat larger than calculated for a spin-only S = 1 localized

t_{2 g}^{4} e_{g}^{0}

electron configuration for a low spin state:

μ_{p}

= 3.22

μ_{B}

and

Θ

=

- 100

K [15,20]. Possibly, the formation of Ru-4d bands could be responsible for these deviations [15,20]. Also for La

_{2}

ZnRuO

_{6}

, a similar behavior with

μ_{p}

= 3.24

μ_{B}

and

Θ

=

- 80

K was observed [20]. For both compounds, the magnetic susceptibility deviates from Curie–Weiss behavior below about 250 K [20].

Here, we report the crystal growth, structure, and properties of a new double perovskite with the nominal composition Y

_{2}

MgRuO

_{6}

that cannot be synthesized at ambient pressure and high-temperature conditions.

2. Results and Discussion

Single crystals of Y

_{2}

MgRuO

_{6}

were grown by the floating zone technique—see Figure 1a for a Laue diffraction pattern of an as-grown crystal. The starting materials Y

_{2}

O

_{3}

, RuO

_{2}

and MgO were mixed in stoichiometric amounts with 100% RuO

_{2}

excess for a compensation of RuO

_{2}

evaporation (see also other ruthenate growth reports, e.g., ref. [21] and references therein). This mixture was thoroughly ground and pressed into rods of ∼5 mm in diameter. These rods were sintered in air at 1100

^{\circ}

C for 24 h. The subsequent floating zone growth was performed at a growth rate of 15 mm/h under an O

_{2}

/Ar atmosphere of 10 bar (with a ratio of 1:10) at a temperature of about 1800

^{\circ}

C. Despite the large excess of RuO

_{2}

, the fast growth rate was still necessary to cope with the heavy evaporation of RuO

_{2}

during crystal growth.

Figure 1. (a) Laue diffraction pattern of an as-grown Y

_{2}

MgRuO

_{6}

crystal. (b) EDX map showing inclusions of Y

_{2}

O

_{3}

and MgO assigned by EBSD pattern evaluation.

Attempts to synthesize polycrystalline Y

_{2}

MgRuO

_{6}

samples using a conventional solid state synthesis route failed. For these polycrystalline samples, stoichiometic amounts of Y

_{2}

O

_{3}

, MgO, and RuO

_{2}

were mixed and first reacted at 950

^{\circ}

C for 24 h followed by sintering at 1200

^{\circ}

C for 48 h. However, powder X-ray diffraction measurements did not show any evidence for a Y

_{2}

MgRuO

_{6}

phase in these powder samples. Instead, an Y

_{2}

Ru

_{2}

O

_{7}

pyrochlore phase [22] was found, together with impurity phases of Y

_{2}

O

_{3}

and MgO.

An electron back-scatter diffraction (EBSD) measurement of a part of the as-grown boule shows a homogeneous phase distribution with grains of the monoclinic Y

_{2}

MgRuO

_{6}

majority phase and the Y

_{2}

O

_{3}

and MgO phases at the grain boundaries, see Figure 1b. It was possible to extract single crystalline grains of up to ≈30–40

μ

m dimension from the floating zone grown crystal, which could be used for further measurements.

The composition of the as-grown polycrystalline material was analyzed using wavelength dispersive X-ray (WDX) on an electron microprobe. The following ratios were obtained for the atomic concentrations of the metals—Y:Mg:Ru = 2.00(1):0.85(1):1.11(1). The oxygen concentration was not determined. Moreover, the composition was found to be homogeneous within each grain of Y

_{2}

MgRuO

_{6}

.

Powder X-ray diffraction measurements of a crushed crystal reveal the appearance of Y

_{2}

O

_{3}

and MgO impurity phases with a volume fraction of 22.5(1)% and 7.1(3)% respectively, see Figure 2. Nonetheless, the ∼70% majority phase of Y

_{2}

MgRuO

_{6}

could be refined properly. The obtained lattice constants and structural parameters are listed in Table 1. A refinement of the occupancies of Ru and Mg at the two B-sites reveals a composition of Y

_{2}

Mg

_{0.902 (4)}

Ru

_{1.098 (4)}

O

_{6}

which is close to the composition of Y

_{2.00 (1)}

Mg

_{0.85 (1)}

Ru

_{1.11 (1)}

O

_{6}

indicated by the WDX measurements.

Figure 2. Powder X-ray diffraction pattern of Y

_{2}

MgRuO

_{6}

(phase 1) together with impurity phases of Y

_{2}

O

_{3}

(phase 2) and MgO (phase 3);

I_{d i f f}

=

I_{o b s} - I_{c a l}

.

Table 1. Refinement results of powder X-ray diffraction measurements of a powderized crystal of Y

_{2}

MgRuO

_{6}

with space group

P 2_{1} / n

(R

_{p}

:8.55%, wR

_{p}

:12.08%). The obtained composition is Y

_{2}

Mg

_{0.902 (4)}

Ru

_{1.098 (4)}

O

_{6}

. There was no indication of a Y deficiency. The oxygen content was not refined. For the atomic positions of the light oxygen ions and for the isotropic displacement parameters

U_{i s o}

of all atoms, the results of our single crystal X-ray diffraction measurements (of sample B) were used.

For an accurate structural analysis, two single crystals with dimensions of the order of 10

μ

m were prepared from the original as-grown crystal (sample A and B). Single crystal X-ray diffraction scattering intensities are shown in Figure 3a–c. For sample A, 4677 reflections were collected up to 2

Θ_{m a x}

= 55.8

^{\circ}

with a redundancy of 9.10 and an internal R value of 4.02%, whereas 32,124 reflections were collected up to 2

Θ_{m a x}

= 90.3

^{\circ}

with a redundancy of 17.89 and an internal R value of 4.74% for sample B. Both measured single crystals show the expected monoclinic twinning for monoclinic systems (with a monoclinic angle

β

= 90.178(1)

^{\circ}

) with twin fractions of close to 50%, see Table 2. The finally obtained crystal structure is that of a double perovskite as shown in Figure 3d.

Figure 3. (a–c) X-ray scattering intensities (displayed in a black/white representation) within

H K 0

,

0 K L

and

H 0 L

planes of reciprocal space (for the measurement of sample B). Green circles indicate the positions for expected Bragg reflections according to space group

P 2_{1} / n

. (d) Crystal structure of Y

_{2}

MgRuO

_{6}

; white/green/magenta/blue spheres: Y/B/

B^{'}

/oxygen ions; the B-site is predominantly occupied by Ru and the

B^{'}

-site, mainly by Mg.

Table 2. Crystallographic and structural refinement data of two single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample A and sample B). The crystallographic software Jana2006 was used for the structural refinement [23];

^{★}

: unobserved reflections (

I < 3 σ (I)

) were used in the refinement. Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction listed in Table 1 because of poorer resolution and monoclinic twinning.

An initial refinement of the occupancies of Ru versus Mg at both of the two B-sites reveals compositions of Y

_{2}

Mg

_{0.867 (4)}

Ru

_{1.133 (4)}

O

_{6}

for sample A and Y

_{2}

Mg

_{0.853 (2)}

Ru

_{1.147 (2)}

O

_{6}

for sample B. From the composition Y

_{2}

Mg

_{0.853 (2)}

Ru

_{1.147 (2)}

O

_{6}

one would nominally expect a Ru 3.74+ oxidation state appearing in this double perovskite compound. But chemically, a Ru

^{4 +}

oxidation state is expected for these growth conditions. In order to obtain the rather stable Ru

^{4 +}

oxidation state, there would have to be nominally a 5% Y-deficiency of

- 0.1

in Y

_{2}

Mg

_{0.853 (2)}

Ru

_{1.147 (2)}

O

_{6}

which would be in agreement with (i) the appearance of an Y

_{2}

O

_{3}

impurity phase in the as-grown crystal, (ii) with somewhat enhanced atomic displacement parameters of the Y ions observed in the refinement and, on the other hand, also (iii) with the compact 113-perovskite structure that does not allow for interstitial sites for excess oxygen. Therefore, the Y occupancy is also refined in a subsequent step. Indeed, this refinement yields compositions of Y

_{1.909 (16)}

Mg

_{0.941 (9)}

Ru

_{1.059 (9)}

O

_{6}

(sample A) and Y

_{1.880 (8)}

Mg

_{0.953 (4)}

Ru

_{1.047 (4)}

O

_{6}

(sample B) that exhibit Y deficiencies. (Due to the refinement of the Y occupancy, an improvement of the R-values could be achieved—e.g., for sample B, the weighted R-value

R_{w}

decreased from 5.41% to 5.09%. Furthermore, the

B / B^{'}

-site disorder was also altered—e.g., the Ru1 occupancy decreased from 0.770(2) to 0.709(4) and the Mg1 occupancy increased from 0.623(2) to 0.661(3) for sample B. On the other hand, the other structural parameters x, y, z and the twin fractions remained very stable). The finally obtained structural parameters and refinement results are listed in Table 2, Table 3 and Table 4. These finally obtained compositions would be consistent with a Ru

^{4 +}

oxidation state, assuming the presence of oxygen deficiencies

δ

, i.e., the occupancy of the oxygen ions should be 98.73% and 97.78% for samples A and B, respectively. (Otherwise, there would be a small admixture of Ru

^{5 +}

ions for

δ

= 0). We did not refine the occupancies of the oxygen ions and set their occupancies to 100% within the refinement since then there would be too many free parameters together with the scale factor. The refined compositions Y

_{1.909 (16)}

Mg

_{0.941 (9)}

Ru

_{1.059 (9)}

O

_{6 - δ}

and Y

_{1.880 (8)}

Mg

_{0.953 (4)}

Ru

_{1.047 (4)}

O

_{6 - δ}

for the two samples are very roughly consistent with each other. Why the

B / B^{'}

-site mixing for these two single crystals is larger than for the powder sample is unclear. One reason could be that the two single crystals originate from a less-ordered part of the as-grown boule. Another possibility would be that single crystal X-ray diffraction gives more accurate results.

Table 3. Refinement results of single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample A). Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction. Therefore, only the values in Table 1 should be used.

Table 4. Refinement results of single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample B). Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction. Therefore, only the values in Table 1 should be used.

Due to the presence of

B / B^{'}

-site mixing, the bond valence sum (BVS) formalism seems not very reliable to determine the Ru oxidation state since the so-called Ru-O distances are only a (weighted) average of Ru-O and Mg-O distances due to the

B / B^{'}

-site disorder. Note that the ionic radii of Mg

^{2 +}

ions is about 0.1 Å larger than that of the Ru ions. And as expected, the formal BVS of Ru ions is lower than for a Ru

^{4 +}

ion, i.e., 3.522(9)+ for Ru1

^{(B)}

, and correspondingly, these BVS values are somewhat larger than expected for a Mg

^{2 +}

ion, i.e., 2.378(6)+ for Mg1

^{(B)}

.

The temperature dependence of magnetic susceptibility

χ (T)

for the nominal composition of Y

_{2}

MgRuO

_{6}

is shown in Figure 4a. The behavior of

χ (T)

resembles that of La

_{2}

MgRuO

_{6}

and La

_{2}

ZnRuO

_{6}

[15,20]. There is no clear evidence for any magnetic order in Y

_{2}

MgRuO

_{6}

. In Figure 4a, the inverse magnetic susceptibility is also plotted. As expected for Curie–Weiss behavior, a rather linear regime can be observed above 300 K (as compared to 250 K in La

_{2}

MgRuO

_{6}

and La

_{2}

ZnRuO

_{6}

[15,20]). A Curie–Weiss fit yields an effective moment of 2.67(35)

μ_{B}

per formula unit, which is only slightly less than the expected spin-only value for a S = 1 system. This result corroborates that the Ru ions are in a S = 1 Ru

^{4 +}

oxidation state. Note that

χ (T)

is also not temperature independent as would be expected for a

J = 0

system. Finally, the Weiss-temperature

Θ

amounts to 27.6(2.8) K, which is indicative for ferromagnetic exchange interactions. This is different from La

_{2}

MgRuO

_{6}

and La

_{2}

ZnRuO

_{6}

where a negative Weiss temperature was observed and might be either related to smaller bond angles due to the small size of the Y ions (the Ru-O-Mg bond angles amount to 143.0(1)

^{\circ}

in Y

_{2}

MgRuO

_{6}

) or to a higher degree of

B / B^{'}

-site disorder in our sample. This significant amount of

B / B^{'}

-site disorder (observed by precise single crystal X-ray diffraction measurements) is also very likely responsible for the lack of magnetic order and also for the S = 1 state due to clustering of Ru at the microscopic level since it leads to a very significant amount of Ru-O-Ru exchange paths instead of the separation of the RuO

_{6}

octahedra by Mg ions in a hypothetical crystal with perfect

B / B^{'}

-site order.

Figure 4. (a) The temperature dependence of magnetic susceptibility and inverse susceptibility of Y

_{2}

MgRuO

_{6}

(

χ_{0}

was obtained from the Curie–Weiss fit, and

χ - χ_{0}

is plotted in order to visualize the linear behavior of the corresponding inverse susceptibility between 300 K and 400 K). (b) Magnetization

M (H)

measured at different temperatures of Y

_{2}

MgRuO

_{6}

.

Isothermal magnetization

M (H)

measurements of Y

_{2}

MgRuO

_{6}

are shown in Figure 4b. At 2 K, the magnetization shows an S-shaped field dependence, which could be explained by the presence of ferromagnetic exchange interactions in this compound, indicated by the positive Weiss temperature.

3. Materials and Methods

Y

_{2}

MgRuO

_{6}

crystals were grown in an optical floating zone furnace (HKZ from Scientific Instruments Dresden GmbH, Dresden, Germany) equipped with a Xe lamp. The synthesis temperature was of the order of ≈1800

^{\circ}

C. As starting materials, RuO

_{2}

(Aldrich 99.9%), Y

_{2}

O

_{3}

(Alfa Aesar 99.9%) and MgO (Alfa Aesar 99.95%) were used.

Powder X-ray diffraction (XRD) measurements were performed on a powder X-ray diffractometer (Bruker D8 Discover A25, Bruker AXS GmbH, Karlsruhe, Germany) (Cu

K_{α 1}

radiation) diffractometer at room temperature.

Single crystal X-ray diffraction (XRD) measurements were performed on a single crystal X-ray diffractometer (Bruker D8, Bruker AXS GmbH, Karlsruhe, Germany) with a bent graphite monochromator for about 3 times the intensity enhancement that is equipped with a Photon III CMOS area detector (Mo

K_{α}

radiation).

The magnetization and susceptibility measurements were performed using a Magnetic Property Measuring System (MPMS), Quantum Design, San Diego, CA, USA.

Wavelength dispersive X-ray analysis was performed on an electron microprobe (Cameca, SX100, Munich, Germany). Electron backscatter diffraction (EBSD) measurements were realized on a scanning electron microscope (JSM-7800F, Jeol (Germany GmbH), Munich, Germany) equipped with an EBSD system (CrystAlign, Bruker Nano GmbH, Berlin, Germany).

4. Conclusions

Single crystals of a new double perovskite—Y

_{2}

MgRuO

_{6}

—could be synthesized with the floating zone technique. The fact that the solid state synthesis of powder samples of the nominal composition Y

_{2}

MgRuO

_{6}

entirely failed might indicate that the synthesis conditions (c,p,T) reached within the growth chamber could be important for the successful growth of this phase. Due to inclusions of Y

_{2}

O

_{3}

and MgO impurity phases, only crystal sizes of up to ∼40

μ

m could be prepared from the as-grown boule. Powder and single crystal X-ray diffraction measurements indicate a monoclinic crystal structure with space group

P 2_{1} / n

and a monoclinic angle

β

= 90.178(1)

^{\circ}

. In addition, these measurements indicate a small excess of Ru and non-negligible

B / B^{'}

-site mixing in this compound. Single crystal X-ray diffraction measurements reveal a composition of Y

_{1.880 (8)}

Mg

_{0.953 (4)}

Ru

_{1.047 (4)}

O

_{6 - δ}

for one of these crystals. The magnetic susceptibility of this double perovskite resembles that of La

_{2}

MgRuO

_{6}

or La

_{2}

ZnRuO

_{6}

. There is no clear indication for any long-range magnetic order in this material. Also, no Van Vleck-type temperature-independent magnetism—as expected for a

J = 0

system—can be observed in this compound. Instead, the effective moment obtained from a Curie–Weiss fit is indicative for a S = 1 Ru

^{4 +}

state. This could be probably the consequence of the

B / B^{'}

-site disorder, which induces a large amount of Ru-O-Ru exchange paths like in single perovskites as, for example, SrRuO

_{3}

. In contrast to La

_{2}

MgRuO

_{6}

or La

_{2}

ZnRuO

_{6}

, the Weiss constant

Θ

is positive, indicating ferromagnetic exchange interactions in Y

_{2}

MgRuO

_{6}

.

Author Contributions

Project management: A.C.K. and L.H.T.; crystal growth: S.R. and A.C.K.; magnetization and powder XRD measurements: S.R. and A.C.K.; single crystal XRD measurements: A.C.K.; EDX/WDX/EBSD measurements: U.B.; manuscript writing: S.R. and A.C.K. with contributions from the other authors. All authors have read and agreed to the published version of the manuscript.

Funding

The research was partly supported by the Deutsche Forschungsgemeinschaft through SFB1143 (project number 247310070).

Data Availability Statement

The data that support the findings of this study are available upon reasonable request.

Conflicts of Interest

The authors declare no conflict of interest.

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Figure 1. (a) Laue diffraction pattern of an as-grown Y

_{2}

MgRuO

_{6}

crystal. (b) EDX map showing inclusions of Y

_{2}

O

_{3}

and MgO assigned by EBSD pattern evaluation.

Figure 2. Powder X-ray diffraction pattern of Y

_{2}

MgRuO

_{6}

(phase 1) together with impurity phases of Y

_{2}

O

_{3}

(phase 2) and MgO (phase 3);

I_{d i f f}

=

I_{o b s} - I_{c a l}

.

Figure 3. (a–c) X-ray scattering intensities (displayed in a black/white representation) within

H K 0

,

0 K L

and

H 0 L

planes of reciprocal space (for the measurement of sample B). Green circles indicate the positions for expected Bragg reflections according to space group

P 2_{1} / n

. (d) Crystal structure of Y

_{2}

MgRuO

_{6}

; white/green/magenta/blue spheres: Y/B/

B^{'}

/oxygen ions; the B-site is predominantly occupied by Ru and the

B^{'}

-site, mainly by Mg.

Figure 4. (a) The temperature dependence of magnetic susceptibility and inverse susceptibility of Y

_{2}

MgRuO

_{6}

(

χ_{0}

was obtained from the Curie–Weiss fit, and

χ - χ_{0}

is plotted in order to visualize the linear behavior of the corresponding inverse susceptibility between 300 K and 400 K). (b) Magnetization

M (H)

measured at different temperatures of Y

_{2}

MgRuO

_{6}

.

Table 1. Refinement results of powder X-ray diffraction measurements of a powderized crystal of Y

_{2}

MgRuO

_{6}

with space group

P 2_{1} / n

(R

_{p}

:8.55%, wR

_{p}

:12.08%). The obtained composition is Y

_{2}

Mg

_{0.902 (4)}

Ru

_{1.098 (4)}

O

_{6}

. There was no indication of a Y deficiency. The oxygen content was not refined. For the atomic positions of the light oxygen ions and for the isotropic displacement parameters

U_{i s o}

of all atoms, the results of our single crystal X-ray diffraction measurements (of sample B) were used.

Table 1. Refinement results of powder X-ray diffraction measurements of a powderized crystal of Y

_{2}

MgRuO

_{6}

with space group

P 2_{1} / n

(R

_{p}

:8.55%, wR

_{p}

:12.08%). The obtained composition is Y

_{2}

Mg

_{0.902 (4)}

Ru

_{1.098 (4)}

O

_{6}

. There was no indication of a Y deficiency. The oxygen content was not refined. For the atomic positions of the light oxygen ions and for the isotropic displacement parameters

U_{i s o}

of all atoms, the results of our single crystal X-ray diffraction measurements (of sample B) were used.

Atom	Wyck.	occ.	x	y	z	U $_{i s o}$ (Å $^{2}$ )
Ru1	2d	0.972(4)	0	1/2	1/2	0.00346
Y1	4e	1	0.9786(3)	0.92820(17)	0.24838(17)	0.007393
Mg1	2c	0.874(3)	1/2	0	1/2	0.005096
O1	4e	1	0.1872	0.8066	0.5596	0.0077
O2	4e	1	0.1872	0.8063	0.9425	0.0071
O3	4e	1	0.1181	0.5444	0.2507	0.007
Mg2	2d	0.028(4)	0	1/2	1/2	0.00346
Ru2	2c	0.126(3)	1/2	0	1/2	0.005096
latt. param.	value
a (Å)	5.29465(6)
b (Å)	5.66404(6)
c (Å)	7.6080(1)
$β$ ( $^{\circ}$ )	90.178(1)

Table 2. Crystallographic and structural refinement data of two single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample A and sample B). The crystallographic software Jana2006 was used for the structural refinement [23];

^{★}

: unobserved reflections (

I < 3 σ (I)

) were used in the refinement. Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction listed in Table 1 because of poorer resolution and monoclinic twinning.

Table 2. Crystallographic and structural refinement data of two single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample A and sample B). The crystallographic software Jana2006 was used for the structural refinement [23];

^{★}

: unobserved reflections (

I < 3 σ (I)

) were used in the refinement. Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction listed in Table 1 because of poorer resolution and monoclinic twinning.

Crystal	Sample A	Sample B
Temperature	room temperature	room temperature
Wavelength	Mo K $_{α}$	Mo K $_{α}$
Crystal system	monoclinic	monoclinic
Space group	P $2_{1} / n$ (14)	P $2_{1} / n$ (14)
Unit cell dimensions	a = 5.2834(13) Å	a = 5.2885(15) Å
	b = 5.6571(13) Å	b = 5.6670(17) Å
	c = 7.6134(16) Å	c = 7.6114(14) Å
	$β$ = 90.134(11) $^{\circ}$	$β$ = 89.996(2) $^{\circ}$
Volume	227.55(9) Å $^{3}$	228.11(10) Å $^{3}$
Z	4	4
F(000)	373	373
Crystal size	∼10–30 $μ$ m	∼10–30 $μ$ m
2 $Θ_{m a x}$	55.8 $^{\circ}$	90.3 $^{\circ}$
Index range	h: −6 → 6	h: −10 → 10
	k: −7 → 7	k: −11 → 11
	l: −9 → 9	l: −15 → 15
Reflections in total/independent	4677/514	32,124/1796
Observed reflections/independent	4102/476	23,056/1524
Internal R-value	4.02%	4.74%
Completeness up to 2 $Θ_{m a x}$	98.5%	94%
Completeness up to 2 $Θ$ = 87.15 $^{\circ}$		98%
Absorption correction	multi-scan	multi-scan
Min./max. transmission	0.5486/0.7456	0.6431/0.7489
Refinement method	least squares on $F^{2}$	least squares on $F^{2}$
Reflections threshold $^{★}$	$I > 3 σ (I)$	$I > 3 σ (I)$
Monoclinic twin fraction 1	54.0(3)%	50.7(2)%
Goodness of fit	1.61	1.42
R/R $_{w}$	2.13%/4.99%	2.26%/5.09%

Table 3. Refinement results of single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample A). Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction. Therefore, only the values in Table 1 should be used.

Table 3. Refinement results of single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample A). Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction. Therefore, only the values in Table 1 should be used.

Composition: Y $_{1.909 (16)}$ Mg $_{0.941 (9)}$ Ru $_{1.059 (9)}$ O $_{6}$
atom	occ.	x	y	z	U $_{i s o}$ (Å $^{2}$ )
Ru1	0.786(10)	0	0.5	0.5	0.0045(2)
Y1	0.955(8)	0.97912(8)	0.92762(9)	0.24949(9)	0.00884(18)
Mg1	0.727(6)	0.5	0	0.5	0.0070(4)
O1	1	0.1852(9)	0.8040(7)	0.5605(5)	0.0110(12)
O2	1	0.1881(8)	0.8084(7)	0.9424(6)	0.0119(13)
O3	1	0.1178(6)	0.5453(6)	0.2520(6)	0.0117(10)
Mg2	0.214(10)	0	0.5	0.5	0.0045(2)
Ru2	0.273(6)	0.5	0	0.5	0.0070(4)
atom	U $_{11}$ (Å $^{2}$ )	U $_{22}$ (Å $^{2}$ )	U $_{33}$ (Å $^{2}$ )	U $_{12}$ (Å $^{2}$ )	U $_{13}$ (Å $^{2}$ )	U $_{23}$ (Å $^{2}$ )
Ru1	0.0045(3)	0.0044(4)	0.0045(3)	0.0007(14)	0.0026(8)	0.0008(9)
Y1	0.0089(3)	0.0079(3)	0.0098(3)	0.00059(17)	−0.0011(13)	−0.00014(15)
Mg1	0.0066(7)	0.0072(8)	0.0071(7)	0.002(3)	0.003(3)	−0.0006(18)
O1	0.012(2)	0.0095(18)	0.012(2)	−0.0006(19)	0.000(2)	−0.0019(15)
O2	0.012(2)	0.0083(18)	0.015(3)	−0.0026(19)	−0.001(2)	0.0002(15)
O3	0.0124(16)	0.0126(18)	0.0102(18)	−0.0008(13)	0.002(3)	−0.0006(17)
Mg2	0.0045(3)	0.0044(4)	0.0045(3)	0.0007(14)	0.0026(8)	0.0008(9)
Ru2	0.0066(7)	0.0072(8)	0.0071(7)	0.002(3)	0.003(3)	−0.0006(18)

Table 4. Refinement results of single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample B). Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction. Therefore, only the values in Table 1 should be used.

Table 4. Refinement results of single crystal X-ray diffraction measurements of Y

_{2}

MgRuO

_{6}

(sample B). Note that the lattice parameters determined by single crystal X-ray diffraction are not as reliable as the lattice constants determined by powder X-ray diffraction. Therefore, only the values in Table 1 should be used.

Composition: Y $_{1.880 (8)}$ Mg $_{0.953 (4)}$ Ru $_{1.047 (4)}$ O $_{6}$
atom	occ.	x	y	z	U $_{i s o}$ (Å $^{2}$ )
Ru1	0.709(4)	0	0.5	0.5	0.00327(6)
Y1	0.940(4)	0.97899(4)	0.92746(4)	0.24962(5)	0.00717(5)
Mg1	0.661(3)	0.5	0	0.5	0.00485(12)
O1	1	0.1865(5)	0.8066(4)	0.5595(3)	0.0100(5)
O2	1	0.1880(4)	0.8063(4)	0.9425(3)	0.0088(5)
O3	1	0.1180(3)	0.5444(3)	0.2503(3)	0.0088(3)
Mg2	0.291(4)	0	0.5	0.5	0.00327(6)
Ru2	0.339(3)	0.5	0	0.5	0.00485(12)
atom	U $_{11}$ (Å $^{2}$ )	U $_{22}$ (Å $^{2}$ )	U $_{33}$ (Å $^{2}$ )	U $_{12}$ (Å $^{2}$ )	U $_{13}$ (Å $^{2}$ )	U $_{23}$ (Å $^{2}$ )
Ru1	0.00340(11)	0.00314(11)	0.00326(11)	0.0014(3)	0.0021(2)	−0.0009(3)
Y1	0.00755(8)	0.00573(9)	0.00823(9)	0.00083(6)	−0.0017(4)	−0.00001(8)
Mg1	0.0052(2)	0.0051(2)	0.00433(19)	0.0028(5)	0.0025(6)	0.0023(5)
O1	0.0119(11)	0.0078(8)	0.0104(9)	−0.0007(8)	−0.0014(9)	−0.0014(7)
O2	0.0072(9)	0.0091(8)	0.0102(9)	−0.0024(8)	−0.0031(8)	0.0021(7)
O3	0.0105(5)	0.0094(6)	0.0066(5)	0.0007(4)	−0.0008(10)	−0.0018(7)
Mg2	0.00340(11)	0.00314(11)	0.00326(11)	0.0014(3)	0.0021(2)	−0.0009(3)
Ru2	0.0052(2)	0.0051(2)	0.00433(19)	0.0028(5)	0.0025(6)	0.0023(5)

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Synthesis and Characterization of the Double Perovskite Y₂MgRuO₆

Abstract

1. Introduction

2. Results and Discussion

3. Materials and Methods

4. Conclusions

Author Contributions

Funding

Data Availability Statement

Conflicts of Interest

References

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