Synthesis in molten alkali metal polyselenophosphate fluxes

A new family of transition metal selenophosphate compounds, A2MP2Se6 (A = K, Rb, Cs; M = Mn, Fe) and A2M′2P2Se6 (A = K, Cs; M′ = Cu, Ag)

Timothy J. McCarthy, Mercouri G Kanatzidis

Research output: Contribution to journalArticle

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Abstract

Five isostructural quaternary alkali metal transition metal selenophosphate compounds, K2MnP2Se6 (I), Rb2MnP2Se6 (II), Cs2MnP2Se6 (III), K2FeP2Se6 (IV), and Cs2FeP2Se6 (V), were synthesized by the molten alkali polyselenophosphate flux technique. In addition, the compounds Cs2Cu2P2Se6 (VI), K2Ag2P2Se6 (VII), and Cs2Ag2P2Se6 (VIII) were synthesized similarly but possess different structures. Crystals were grown with M/P4-Se10/A2Se/Se flux reactions at 450°C while pure material was obtained by direct combination of Mn/P/A2Se/Se at 500°C. The structures of I, III, IV, VI, VII, and VIII have been determined by single-crystal X-ray diffraction analysis. Orange crystals of I crystallize in the monoclinic space group P21/n (No. 14) with a = 6.5349(9) Å, b = 12.696(3) Å, c = 7.589(2) Å, β = 102.67(2)°, V = 614.3(4) Å3, and Z =2. Compound III also crystallizes in the space group P21/n (No. 14) with a = 6.4761(9) Å, b = 13.006(2) Å, c = 7.974(1) Å, β = 93.09(1)°, V = 670.6(2) Å3, and Z = 2. Red crystals of IV are X-ray isomorphous to I with a = 6.421(2) Å, b= 12.720(5) Å, c = 7.535(3) Å, β = 102.58(3)°, V = 600.7(7) Å3, and Z = 2. Dark green crystals of VI are also monoclinic, space group P21/c (No. 14), with a = 9.958(3) Å, b = 13.067(3) Å, c = 10.730(2) Å, β = 102.46(2)°, V = 1363(1) Å3, and Z = 4. Orange crystals of VII are monoclinic, space group P21/c (No. 14) with a = 8.528 Å, b = 11.251(6) Å, c = 20.975(4) Å, β = 93.24(3)°, V = 2009(3) Å3, and Z = 4. Yellow rod-like crystals of VIII crystallize in the monoclinic space group P21/n (No. 14) with a = 6.807(3) Å, b = 12.517(3) Å, c = 8.462(3) Å, β = 95.75(3)°, V = 717.3(8) Å3, and Z = 2. The structure of the [MP2Se6]n2n- (M = Mn, Fe) anion (I-V) is closely related to the TiI3 structure type. The transition metal ion and the P-P pairs reside in octahedra that share faces in the a-direction. These chains are well separated by alkali metal ions. The structures of VI and VIII are closely related to those of I-V. Cu⋯Cu and Ag⋯Ag dimers are found in the octahedral metal sites to form the chain structure. The structure of VII is unrelated to the chain structure but forms a three-dimensional tunnel framework consisting of tetrahedral AgSe4 and [P2Se6]4- units. Magnetic susceptibility measurements indicate that I-IV couple antiferromagnetically between 10 and 20 K and the d electrons of M2+ are found in a high-spin state. The band gaps were determined by optical spectroscopy to be 2.33, 2.41, 2.19, 1.72, and 2.02 eV respectively for I-V. The band-gaps of VI-VIII can be assessed at 2.44, 2.39, and 2.55 eV respectively. All compounds melt congruently with I melting at 717°C, II at 781°C, III at 831°C, IV at 662°C, V at 769 °C, VI at 670°C, VII at 542°C, and VIII at 594°C.

Original languageEnglish
Pages (from-to)1257-1267
Number of pages11
JournalInorganic Chemistry
Volume34
Issue number5
Publication statusPublished - 1995

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Transition metal compounds
Alkali Metals
metal compounds
alkali metals
Molten materials
transition metals
Fluxes
Crystals
synthesis
crystals
Metal ions
metal ions
Energy gap
Alkalies
Magnetic susceptibility
Dimers
X ray diffraction analysis
Transition metals
Anions
tunnels

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

@article{fa4fdb28670041e08df22aeec3ddb357,
title = "Synthesis in molten alkali metal polyselenophosphate fluxes: A new family of transition metal selenophosphate compounds, A2MP2Se6 (A = K, Rb, Cs; M = Mn, Fe) and A2M′2P2Se6 (A = K, Cs; M′ = Cu, Ag)",
abstract = "Five isostructural quaternary alkali metal transition metal selenophosphate compounds, K2MnP2Se6 (I), Rb2MnP2Se6 (II), Cs2MnP2Se6 (III), K2FeP2Se6 (IV), and Cs2FeP2Se6 (V), were synthesized by the molten alkali polyselenophosphate flux technique. In addition, the compounds Cs2Cu2P2Se6 (VI), K2Ag2P2Se6 (VII), and Cs2Ag2P2Se6 (VIII) were synthesized similarly but possess different structures. Crystals were grown with M/P4-Se10/A2Se/Se flux reactions at 450°C while pure material was obtained by direct combination of Mn/P/A2Se/Se at 500°C. The structures of I, III, IV, VI, VII, and VIII have been determined by single-crystal X-ray diffraction analysis. Orange crystals of I crystallize in the monoclinic space group P21/n (No. 14) with a = 6.5349(9) {\AA}, b = 12.696(3) {\AA}, c = 7.589(2) {\AA}, β = 102.67(2)°, V = 614.3(4) {\AA}3, and Z =2. Compound III also crystallizes in the space group P21/n (No. 14) with a = 6.4761(9) {\AA}, b = 13.006(2) {\AA}, c = 7.974(1) {\AA}, β = 93.09(1)°, V = 670.6(2) {\AA}3, and Z = 2. Red crystals of IV are X-ray isomorphous to I with a = 6.421(2) {\AA}, b= 12.720(5) {\AA}, c = 7.535(3) {\AA}, β = 102.58(3)°, V = 600.7(7) {\AA}3, and Z = 2. Dark green crystals of VI are also monoclinic, space group P21/c (No. 14), with a = 9.958(3) {\AA}, b = 13.067(3) {\AA}, c = 10.730(2) {\AA}, β = 102.46(2)°, V = 1363(1) {\AA}3, and Z = 4. Orange crystals of VII are monoclinic, space group P21/c (No. 14) with a = 8.528 {\AA}, b = 11.251(6) {\AA}, c = 20.975(4) {\AA}, β = 93.24(3)°, V = 2009(3) {\AA}3, and Z = 4. Yellow rod-like crystals of VIII crystallize in the monoclinic space group P21/n (No. 14) with a = 6.807(3) {\AA}, b = 12.517(3) {\AA}, c = 8.462(3) {\AA}, β = 95.75(3)°, V = 717.3(8) {\AA}3, and Z = 2. The structure of the [MP2Se6]n2n- (M = Mn, Fe) anion (I-V) is closely related to the TiI3 structure type. The transition metal ion and the P-P pairs reside in octahedra that share faces in the a-direction. These chains are well separated by alkali metal ions. The structures of VI and VIII are closely related to those of I-V. Cu⋯Cu and Ag⋯Ag dimers are found in the octahedral metal sites to form the chain structure. The structure of VII is unrelated to the chain structure but forms a three-dimensional tunnel framework consisting of tetrahedral AgSe4 and [P2Se6]4- units. Magnetic susceptibility measurements indicate that I-IV couple antiferromagnetically between 10 and 20 K and the d electrons of M2+ are found in a high-spin state. The band gaps were determined by optical spectroscopy to be 2.33, 2.41, 2.19, 1.72, and 2.02 eV respectively for I-V. The band-gaps of VI-VIII can be assessed at 2.44, 2.39, and 2.55 eV respectively. All compounds melt congruently with I melting at 717°C, II at 781°C, III at 831°C, IV at 662°C, V at 769 °C, VI at 670°C, VII at 542°C, and VIII at 594°C.",
author = "McCarthy, {Timothy J.} and Kanatzidis, {Mercouri G}",
year = "1995",
language = "English",
volume = "34",
pages = "1257--1267",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "5",

}

TY - JOUR

T1 - Synthesis in molten alkali metal polyselenophosphate fluxes

T2 - A new family of transition metal selenophosphate compounds, A2MP2Se6 (A = K, Rb, Cs; M = Mn, Fe) and A2M′2P2Se6 (A = K, Cs; M′ = Cu, Ag)

AU - McCarthy, Timothy J.

AU - Kanatzidis, Mercouri G

PY - 1995

Y1 - 1995

N2 - Five isostructural quaternary alkali metal transition metal selenophosphate compounds, K2MnP2Se6 (I), Rb2MnP2Se6 (II), Cs2MnP2Se6 (III), K2FeP2Se6 (IV), and Cs2FeP2Se6 (V), were synthesized by the molten alkali polyselenophosphate flux technique. In addition, the compounds Cs2Cu2P2Se6 (VI), K2Ag2P2Se6 (VII), and Cs2Ag2P2Se6 (VIII) were synthesized similarly but possess different structures. Crystals were grown with M/P4-Se10/A2Se/Se flux reactions at 450°C while pure material was obtained by direct combination of Mn/P/A2Se/Se at 500°C. The structures of I, III, IV, VI, VII, and VIII have been determined by single-crystal X-ray diffraction analysis. Orange crystals of I crystallize in the monoclinic space group P21/n (No. 14) with a = 6.5349(9) Å, b = 12.696(3) Å, c = 7.589(2) Å, β = 102.67(2)°, V = 614.3(4) Å3, and Z =2. Compound III also crystallizes in the space group P21/n (No. 14) with a = 6.4761(9) Å, b = 13.006(2) Å, c = 7.974(1) Å, β = 93.09(1)°, V = 670.6(2) Å3, and Z = 2. Red crystals of IV are X-ray isomorphous to I with a = 6.421(2) Å, b= 12.720(5) Å, c = 7.535(3) Å, β = 102.58(3)°, V = 600.7(7) Å3, and Z = 2. Dark green crystals of VI are also monoclinic, space group P21/c (No. 14), with a = 9.958(3) Å, b = 13.067(3) Å, c = 10.730(2) Å, β = 102.46(2)°, V = 1363(1) Å3, and Z = 4. Orange crystals of VII are monoclinic, space group P21/c (No. 14) with a = 8.528 Å, b = 11.251(6) Å, c = 20.975(4) Å, β = 93.24(3)°, V = 2009(3) Å3, and Z = 4. Yellow rod-like crystals of VIII crystallize in the monoclinic space group P21/n (No. 14) with a = 6.807(3) Å, b = 12.517(3) Å, c = 8.462(3) Å, β = 95.75(3)°, V = 717.3(8) Å3, and Z = 2. The structure of the [MP2Se6]n2n- (M = Mn, Fe) anion (I-V) is closely related to the TiI3 structure type. The transition metal ion and the P-P pairs reside in octahedra that share faces in the a-direction. These chains are well separated by alkali metal ions. The structures of VI and VIII are closely related to those of I-V. Cu⋯Cu and Ag⋯Ag dimers are found in the octahedral metal sites to form the chain structure. The structure of VII is unrelated to the chain structure but forms a three-dimensional tunnel framework consisting of tetrahedral AgSe4 and [P2Se6]4- units. Magnetic susceptibility measurements indicate that I-IV couple antiferromagnetically between 10 and 20 K and the d electrons of M2+ are found in a high-spin state. The band gaps were determined by optical spectroscopy to be 2.33, 2.41, 2.19, 1.72, and 2.02 eV respectively for I-V. The band-gaps of VI-VIII can be assessed at 2.44, 2.39, and 2.55 eV respectively. All compounds melt congruently with I melting at 717°C, II at 781°C, III at 831°C, IV at 662°C, V at 769 °C, VI at 670°C, VII at 542°C, and VIII at 594°C.

AB - Five isostructural quaternary alkali metal transition metal selenophosphate compounds, K2MnP2Se6 (I), Rb2MnP2Se6 (II), Cs2MnP2Se6 (III), K2FeP2Se6 (IV), and Cs2FeP2Se6 (V), were synthesized by the molten alkali polyselenophosphate flux technique. In addition, the compounds Cs2Cu2P2Se6 (VI), K2Ag2P2Se6 (VII), and Cs2Ag2P2Se6 (VIII) were synthesized similarly but possess different structures. Crystals were grown with M/P4-Se10/A2Se/Se flux reactions at 450°C while pure material was obtained by direct combination of Mn/P/A2Se/Se at 500°C. The structures of I, III, IV, VI, VII, and VIII have been determined by single-crystal X-ray diffraction analysis. Orange crystals of I crystallize in the monoclinic space group P21/n (No. 14) with a = 6.5349(9) Å, b = 12.696(3) Å, c = 7.589(2) Å, β = 102.67(2)°, V = 614.3(4) Å3, and Z =2. Compound III also crystallizes in the space group P21/n (No. 14) with a = 6.4761(9) Å, b = 13.006(2) Å, c = 7.974(1) Å, β = 93.09(1)°, V = 670.6(2) Å3, and Z = 2. Red crystals of IV are X-ray isomorphous to I with a = 6.421(2) Å, b= 12.720(5) Å, c = 7.535(3) Å, β = 102.58(3)°, V = 600.7(7) Å3, and Z = 2. Dark green crystals of VI are also monoclinic, space group P21/c (No. 14), with a = 9.958(3) Å, b = 13.067(3) Å, c = 10.730(2) Å, β = 102.46(2)°, V = 1363(1) Å3, and Z = 4. Orange crystals of VII are monoclinic, space group P21/c (No. 14) with a = 8.528 Å, b = 11.251(6) Å, c = 20.975(4) Å, β = 93.24(3)°, V = 2009(3) Å3, and Z = 4. Yellow rod-like crystals of VIII crystallize in the monoclinic space group P21/n (No. 14) with a = 6.807(3) Å, b = 12.517(3) Å, c = 8.462(3) Å, β = 95.75(3)°, V = 717.3(8) Å3, and Z = 2. The structure of the [MP2Se6]n2n- (M = Mn, Fe) anion (I-V) is closely related to the TiI3 structure type. The transition metal ion and the P-P pairs reside in octahedra that share faces in the a-direction. These chains are well separated by alkali metal ions. The structures of VI and VIII are closely related to those of I-V. Cu⋯Cu and Ag⋯Ag dimers are found in the octahedral metal sites to form the chain structure. The structure of VII is unrelated to the chain structure but forms a three-dimensional tunnel framework consisting of tetrahedral AgSe4 and [P2Se6]4- units. Magnetic susceptibility measurements indicate that I-IV couple antiferromagnetically between 10 and 20 K and the d electrons of M2+ are found in a high-spin state. The band gaps were determined by optical spectroscopy to be 2.33, 2.41, 2.19, 1.72, and 2.02 eV respectively for I-V. The band-gaps of VI-VIII can be assessed at 2.44, 2.39, and 2.55 eV respectively. All compounds melt congruently with I melting at 717°C, II at 781°C, III at 831°C, IV at 662°C, V at 769 °C, VI at 670°C, VII at 542°C, and VIII at 594°C.

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M3 - Article

VL - 34

SP - 1257

EP - 1267

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 5

ER -