High-temperature synthesis according to ceramic technology is used to prepare new manganites NdMe 3 Sr 3 Mn 4 O 12 (Me—Li, Na, K). The X-ray powder method is used to find that the compounds crystallize in tetragonal syngony, and the parameters of their crystal lattices are determined. The method of dynamic calorimetry is used in the range from 298.15 to 673 K for determining the heat capacity of manganites; in so doing, the presence of second-order phase transitions is revealed. In view of phase transitions, equations are derived which describe the dependence C p ℴ ∼ f ( T ) in the range from 298.15 to 673 K. The temperature dependences of permittivity and electrical resistance of manganites are investigated at 303–503 K; these dependences likewise confirm the presence of second-order phase transitions.

Manganites DyM 3 I Mg3Mn4O12 and DyM 3 I Ba3Mn4O12 (MI = Li, Na, K) were synthesized by the solid-state reaction of dysprosium and manganese(III) oxides and magnesium and corresponding alkali metal carbonates. The X-ray powder diffraction studies showed that the crystals are orthozhombic with the following unit cell parameters and densities: DyLi3Mg3Mn4O12—a = 10.88 Å, b = 10.73 Å, c = 19.63 Å, V 0 = 1656.2 Å3, Z = 8, ρcalc = 5.36 g/cm3, ρpycn = 5.11 ± 0.05 g/cm3; DyNaMg3Mn4O12—a = 10.55 Å, b = 10.72 Å, c = 18.28 Å, V 0 = 2067.4 Å3, Z = 8, ρcalc = 4.60 g/cm3, ρpycn = 4.88 ± 0.09 g/cm3; DyK3Mg3Mn4O12—a = 10.56 Å, b = 10.72 Å, c = 20.89 Å, V 0 = 2206.0 Å3, Z = 8, ρcalc = 4.60 g/cm3, ρpycn = 4.92 ± 0.06 g/cm3; DyLi3Ba3Mn4O12—a = 10.53 Å, b = 10.69 Å, c = 21.28 Å, V 0 = 2395.4 Å3, Z = 8, ρcalc = 5.58 g/cm3, ρpycn = 5.98 ± 0.12 g/cm3; DyNa3Ba3Mn4O12—a = 10.53 Å, b = 10.74 Å, c = 23.00 Å, V 0 = 2602.3 Å3, Z = 8, ρcalc = 5.39 g/cm3, ρpycn = 5.30 ± 0.07 g/cm3; DyK3Ba3Mn4O12—a = 10.52 Å, b = 10.75 Å, c = 25.69 Å, V 0 = 2905.2 Å3, Z = 8, ρcalc = 5.04 g/cm3, ρpycn = 5.00 ± 0.18 g/cm3.

Double ferrites ErCaFe2O5.5, ErSrFe2O5.5, and ErBaFe2O5.5 were synthesized by solid-state reactions from erbium and iron(III) oxides and calcium, strontium, and barium carbonates. The compounds were found to crystallize in the orthorhombic system. Their unit cell parameters were determined by X-ray powder diffraction; their densities were measured.

The ceramic technology is employed for synthesizing manganites of composition Nd Mg 3 I Mg3Mn4O12(MeI-Li, Na, K). The X-ray technique is used to find that the compounds crystallize in tetragonal syngony. The parameters of their crystal lattices are determined. Their heat capacities are experimentally determined in the range from 298.15 to 673 K, which enables one to reveal second-order phase transitions. In view of these transitions, equations describing the C p ° ∼ f(T) dependence are derived, and the thermodynamic functions C p ° (T), H°(T)-H°(298.15), S°(T), and Φ xx (T) are calculated.

Manganites NdM 3 Sr 3 Mn 4 O 12 and NdM 3 Ba 3 Mn 4 O 12 (M = Li, Na, K) were synthesized by a ceramic method from the corresponding oxides and carbonates. The X-ray diffraction analysis showed that all the compounds crystallized in the tetragonal crystal system with the following lattice parameters: NdLi 3 Sr 3 Mn 4 O 12 : a = 10.88 Å, c = 9.52 Å, V o = 1126.9 Å 3 , Z = 4, ρ X = 4.95 g/cm 3 , ρ pycn = 4.87 ± 0.05 g/cm 3 ; NdNa 3 Sr 3 Mn 4 O 12 : a = 10.73 Å, c = 10.66 Å, V o = 1227.3 Å 3 , Z = 4, ρ X = 4.80 g/cm 3 , ρ pycn = 4.73 ± 0.07 g/cm 3 ; NdK 3 Sr 3 Mn 4 O 12 : a = 10.87 Å, c = 11.71 Å, V o = 1382.6 Å 3 , Z = 4, ρ X = 4.50 g/cm 3 , ρ pycn = 4.43 ± 0.09 g/cm 3 ; NdLi 3 Ba 3 Mn 4 O 12 : a = 10.97 Å, c = 10.34 Å, V o = 1244.3 Å 3 , Z = 4, ρ X = 5.33 g/cm 3 , ρ pycn = 5.23 ± 0.09 g/cm 3 ; NdNa 3 Ba 3 Mn 4 O 12 : a = 10.99 Å, c = 11.15 Å, V o = 1346.7 Å 3 , Z = 4; ρ X = 5.11 g/cm 3 , ρ pycn = 5.05 ± 0.06 g/cm 3 ; NdK 3 Ba 3 Mn 4 O 12 : a = 10.997 Å; c = 13.80 Å, V o = 1668.9 Å 3 , Z = 4, ρ X = 4.32 g/cm 3 , ρ pycn = 4.26 ± 0.07 g/cm 3 .

NdLi3Mg3Mn4O12, NdNa3Mg3Mn4O12, and NdK3Mg3Mn4O12 manganites were synthesized for the first time by solid phase reactions of neodymium(III) and manganese(III) oxides with lithium, sodium, potassium, and magnesium carbonates. X-ray diffraction showed that the compounds crystallized in the tetragonal crystal system. Their unit cell parameters were determined.

Ytterbium alkali-metal chromites YbMCr 2 O 5 (M = Li, Na, K, Cs) were synthesized by a ceramic procedure from the corresponding oxides and carbonates. Their crystal systems and unit cell parameters were determined by the homology method: for YbLiCr 2 O 5 , a = 10.34 Å, b = 10.62 Å, c = 15.05 Å, Z = 16, V o = 1653.74 Å 3 , ρ X-ray = 5.85 g/cm 3 , ρ pycn = 5.81 ± 0.03 g/cm 3 ; for YbNaCr 2 O 5 , a = 10.30 Å, b = 10.56 Å, c = 16.46 Å, Z = 16, V o = 1790.32 Å 3 , ρ X-ray = 5.64 g/cm 3 , ρ pycn = 5.59 ± 0.07 g/cm 3 ; for YbKCr 2 O 5 , a = 10.33 Å, b = 10.63 Å, c = 19.93 Å, Z = 16, V o = 2188.47 Å 3 , ρ X-ray = 5.95 g/cm 3 , ρ pycn = 5.91 ± 0.03 g/cm 3 ; and for YbCsCr 2 O 5 , a = 10.34 Å, b = 10.63 Å, c = 18.43 Å, Z = 16, V o = 2025.72 Å 3 , ρ X-ray = 5.19 g/cm 3 , ρ pycn = 5.16 ± 0.05 g/cm 3 .

Ternary chromites of the composition LaM I Mg(CrO 3 ) 2 (M I = Li, Na, K) were synthesized for the first time by ceramic technology from stoichiometric amounts of high purity grade La 2 O 3 ; pure for analysis grade Li 2 CO 3 , Na 2 CO 3 , K 2 CO 3 , and MgCO 3 ; and chemically pure grade Cr 2 O 3 . Using X-ray diffractometry, it has been established that compounds are crystallized in cubic and tetragonal crystal systems, and parameters of their crystal lattices have been determined.

Ferrites LaLiMnFeO 5 and LaCsMnFeO 5 were synthesized for the first time by ceramic technology from mixtures of lanthanum(III), manganese, and iron(III) oxides with lithium or cesium carbonate. The compounds were shown by X-ray diffraction to crystallize in the orthorhombic system; the unit cell parameters were determined. The heat capacities were found experimentally for 298.15–673 K. Equations for the heat capacities as a function of temperature were derived and used to calculate the thermodynamic functions C p 0 ( T ), S 0 ( T ), H 0 ( T )− H 0 (298.15), and Φ **( T ) for the above temperature range.

Ternary chromites of the composition LaMIMg(CrO3)(2) (MI = Li, Na, K) were synthesized for the first time by ceramic technology from stoichiometric amounts of high purity grade La2O3; pure for analysis grade Li2CO3, Na2CO3, K2CO3, and MgCO3; and chemically pure grade Cr2O3. Using X-ray diffractometry, it has been established that compounds are crystallized in cubic and tetragonal crystal systems, and parameters of their crystal lattices have been determined.

La 2 M 3 II Mn 4 O 12 (M = Mg, Ca, Sr, or Ba) manganites have been synthesized by ceramic technology from lanthanum oxide, manganese(III) oxide, and magnesium, calcium, strontium, or barium carbonate. X-ray powder diffraction shows that these compounds crystallize in cubic perovskite space group Pm3m .

Manganites LaM 3 I M 3 II Mn 4 O 12 (M I = Li, Na, K; M II = Mg, Ca) have been synthesized for the first time by the solid-phase reactions of lanthanum(III) and manganese(II) oxides and lithium, sodium, potassium, magnesium, and calcium carbonates. X-ray diffraction shows that all of them crystallize in the cubic crystal system. Their unit cell parameters are determined.

New ferrites ErMFe 2 O 5 (M = Li, Na, K) were synthesized from erbium and iron(III) oxides and lithium, sodium, and potassium carbonates by solid-state annealing. According to X-ray powder diffraction, these compounds crystallize in the orthorhombic system with the following unit cell parameters: ErLiFe 2 O 5 , a = 10.510 Å, b = 10.776 Å, c = 14.270 Å, V 0 = 1616.16 Å 3 ; Z = 16, V subcell 0 = 101.01 Å 3 , ρ X = 6.01 g/cm 3 , ρ pycn = 5.97 ± 0.05 g/cm 3 ; ErNaFe 2 O 5 , a = 10.519 Å, b = 10.785 Å, c = 15.510 Å, V 0 = 1759.56 Å 3 , Z = 16, V subcell 0 = 109.90 Å 3 , ρ X = 5.77 g/cm 3 , ρ pycn = 5.72 ± 0.08 g/cm 3 ; ErKFe 2 O 5 , a = 10.050 Å, b = 11.320 Å, c = 15.480 Å, V 0 = 1937.33 Å 3 , Z = 16, V subcell 0 = 121.08 Å 3 , ρ X = 5.46 g/cm 3 , ρ pycn = 5.41 ± 0.04 g/cm 3 .

The GdMCr2O5 (M=Na, K, Cs) chromites are synthesized from Gd2O3, Cr2O3, and M2CO3 by solid-state reactions and are shown to have a tetragonal structure. The heat capacity of the chromites is measured from 298.15 to 673 K using a heat-pulse calorimeter. The data for GdKCr2O5 and GdCsCr2O5 show anomalies at 373 and 398 K, respectively, attributable to a second-order phase transition. The best fit equations for the C p 0 (T) data are derived. Electrical measurements in the range 303–383 K attest to semiconducting behavior of the chromites.

The method of dynamic calorimetry is used to investigate the heat capacity of chromite NdLiCr2O5 in the temperature range from 298 to 673 K. A λ-like peak is observed at 523 K.The equations of temperature dependence of the heat capacity of this chromite are derived.The temperature dependences of the thermodynamic functions are calculated.The results of electrophysical investigations indicate that this compound may be classed with semiconductors.

A new chromite GdBaCr2O5.5 was synthesized by ceramic technology and characterized using X-ray powder diffraction. The compound crystallizes in a tetragonal crystal system with a = 10.77 angstrom, c = 17.90 angstrom, V = 2076.3 angstrom(3), Z = 16, V-subcell = 129.8, angstrom(3), rho(x-ray) = 6.22 g/cm(3), rho(pycn) = (6.17 +/- 0.04) g/cm(3). The heat capacity for the new chromite was experimentally determined in the range from 298.15 to 673 K, equations for the heat capacity were derived, and the thermodynamic functions C degrees(p) (T), H degrees(T) - H degrees(298.15), S degrees(T), and P Phi**(T) were calculated. Second-order phase transitions at 348 and 548 K were found in the heat capacity trend, which are likely due to the paramagnetism of gadolinium ions. The dielectric constant and electrical resistance C, versus temperature measurements showed several features that are in correlation with the calorimetric heat capacity measurements and prove that the chromite has semiconductor properties.

The solid-phase method is used to synthesize GdCaCr 2 O 5.5 chromite from chrome and gadolinium oxides and calcium carbonate. X-ray phase analysis is used to find that the compound is crystallized in tetragonal crystal system with the following lattice parameters: a = 10.77 Å, c = 15.84 Å, V = 183.3 Å 3 , Z = 16, V unit cell = 11.8 Å, ρ X-ray = 5.63, and ρ pycn = 5.55+0.05 g/cm 3 . An IT-S-400 calorimeter is used to measure the heat capacity of the compound in the temperature range from 298.15 to 673 K. Pronounced anomalous jumps are observed on the heat capacity curve at 448 and 473 K, which are apparently associated with second- order phase transitions. Equations describing the C p ≈ f ( T ) dependence are derived, and the functions C p ( T ), S ( T ), H ( T ) - H (298.15), and Φ xx ( T ) of chromite in the range from 298.15 to 673 K are calculated. The temperature dependences of dielectric permittivity and electric resistance of the compound are investigated in the range from 303 to 383 K to demonstrate that chromite under investigation exhibits semiconductor properties.

The manganites (MMgDyMn2O6)-Mg-1 (M-I = Li, Na, K, Cs) were synthesized by solid-state annealing from dysprosium oxide, manganese oxide, magnesium carbonate, and alkali metal carbonate. According to X-ray diffraction, these compounds crystallize in the orthorhombic system with the following unit cell parameters : LiMoDyMn2O6, a = 10.54 Angstrom, b = 10.72 Angstrom, c = 17.08 Angstrom, Vdegrees = 1929.9 Angstrom(3), V(cell)degrees =120.6 Angstrom(3), Z = 16, rho(x) = 5.49 g/cm(3), rho(pycn) = (5.30 +/- 0.06) g/cm(3); NaMgDyMn2O6, a = 10.55 Angstrom, b = 10.73 Angstrom, c = 16.92 Angstrom, Vdegrees = 1915.4 Angstrom(3), V(cell)degrees = 119.7 Angstrom(3), Z = 16, rho(x) = 5.76 g/cm(3), rho(pycn) = (5.65+/-0.09) g/cm(3); KMgDyMn2O6, a = 10.60Angstrom, b = 10.75Angstrom, c = 16.83 Angstrom, Vdegrees = 1917.1 Angstrom(3), V(cell)degrees = 119.8 Angstrom(3) Z=16, rho(x) = 5.98 rho(pycn) = (5.90+/-0.05) g/cm(3); CsMgDyMn2O6, a = 10.56 Angstrom, b = 10.74 Angstrom, c = 17.02 Angstrom, Vdegrees = 1930.3 Angstrom(3), Vdegrees(cell) = 120.6 Angstrom(3), Z = 16, rho(x) = 7.23 g/cm(3) rho(pycn) = (7.14 +/- 0.07) g/cm(3).