Jahn-Teller distorted frameworks and magnetic order in the Rb-Mn-P-O system

Fiona C. Coomer, Neal J. Checker, Adrian J. Wright

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Two previously uncharacterized members of the Rb-Mn-P-O system, RbMnP2O7 and beta-RbMnHP3O10, have been synthesized using a phosphoric acid flux synthetic route and their crystal and magnetic structures determined using neutron powder diffraction. The crystal structure of RbMnP2O7 (space group P2(1)/c, a = 7.3673(2) angstrom, b = 9.6783(2) angstrom, c = 8.6467(2) angstrom, and beta = 105.487(1)degrees) was found to be isostructural with RbFeP2O7. The polymorph beta-RbMnHP3O10 was also isolated as a single phase and found to crystallize in the space group C2 (a = 12.2066(5) angstrom, b = 8.5243(3) angstrom, c = 8.8530(4) angstrom, beta = 107.233(2)degrees). Both structures consist of frameworks of corner-sharing MnO6 octahedra linked together by condensed phosphate anions, with Rb+ cations located in the intersecting channels. In both cases the Mn3+ octahedra exhibit unusual Jahn-Teller distortions indicative of a plasticity effect driven by the steric requirements of the condensed phosphate anions, and this causes a strong violet coloration similar to that observed in the manganese violet pigment; the structure of this has yet to be determined. Magnetic susceptibility measurements show that both RbMnP2O7 (T-N = 20 K) and beta-RbMnHP3O10 (T-N = 10 K) undergo a phase transition at low temperatures to an antiferromagnetically ordered state. Low-temperature neutron powder diffraction studies show that the magnetic ground states of each of these materials involve both ferromagnetic and antiferromagnetic super-superexchange interactions between orbitally ordered Mn3+, which are mediated by PO4 tetrahedra. These interactions are compared and discussed.

LanguageEnglish
Pages934-942
Number of pages9
JournalInorganic Chemistry
Volume49
Issue number3
DOIs
Publication statusPublished - 1 Feb 2010

Fingerprint

Neutron powder diffraction
Anions
phosphates
Crystal structure
Phosphates
anions
neutrons
Jahn-Teller effect
crystal structure
phosphoric acid
Magnetic structure
Manganese
pigments
Polymorphism
Magnetic susceptibility
diffraction
Pigments
plastic properties
tetrahedrons
Ground state

Keywords

  • crystal structures
  • phosphates
  • refinement
  • complexes
  • cesium

Cite this

Coomer, Fiona C. ; Checker, Neal J. ; Wright, Adrian J. / Jahn-Teller distorted frameworks and magnetic order in the Rb-Mn-P-O system. In: Inorganic Chemistry. 2010 ; Vol. 49, No. 3. pp. 934-942.
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abstract = "Two previously uncharacterized members of the Rb-Mn-P-O system, RbMnP2O7 and beta-RbMnHP3O10, have been synthesized using a phosphoric acid flux synthetic route and their crystal and magnetic structures determined using neutron powder diffraction. The crystal structure of RbMnP2O7 (space group P2(1)/c, a = 7.3673(2) angstrom, b = 9.6783(2) angstrom, c = 8.6467(2) angstrom, and beta = 105.487(1)degrees) was found to be isostructural with RbFeP2O7. The polymorph beta-RbMnHP3O10 was also isolated as a single phase and found to crystallize in the space group C2 (a = 12.2066(5) angstrom, b = 8.5243(3) angstrom, c = 8.8530(4) angstrom, beta = 107.233(2)degrees). Both structures consist of frameworks of corner-sharing MnO6 octahedra linked together by condensed phosphate anions, with Rb+ cations located in the intersecting channels. In both cases the Mn3+ octahedra exhibit unusual Jahn-Teller distortions indicative of a plasticity effect driven by the steric requirements of the condensed phosphate anions, and this causes a strong violet coloration similar to that observed in the manganese violet pigment; the structure of this has yet to be determined. Magnetic susceptibility measurements show that both RbMnP2O7 (T-N = 20 K) and beta-RbMnHP3O10 (T-N = 10 K) undergo a phase transition at low temperatures to an antiferromagnetically ordered state. Low-temperature neutron powder diffraction studies show that the magnetic ground states of each of these materials involve both ferromagnetic and antiferromagnetic super-superexchange interactions between orbitally ordered Mn3+, which are mediated by PO4 tetrahedra. These interactions are compared and discussed.",
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Jahn-Teller distorted frameworks and magnetic order in the Rb-Mn-P-O system. / Coomer, Fiona C.; Checker, Neal J.; Wright, Adrian J.

In: Inorganic Chemistry, Vol. 49, No. 3, 01.02.2010, p. 934-942.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Jahn-Teller distorted frameworks and magnetic order in the Rb-Mn-P-O system

AU - Coomer, Fiona C.

AU - Checker, Neal J.

AU - Wright, Adrian J.

PY - 2010/2/1

Y1 - 2010/2/1

N2 - Two previously uncharacterized members of the Rb-Mn-P-O system, RbMnP2O7 and beta-RbMnHP3O10, have been synthesized using a phosphoric acid flux synthetic route and their crystal and magnetic structures determined using neutron powder diffraction. The crystal structure of RbMnP2O7 (space group P2(1)/c, a = 7.3673(2) angstrom, b = 9.6783(2) angstrom, c = 8.6467(2) angstrom, and beta = 105.487(1)degrees) was found to be isostructural with RbFeP2O7. The polymorph beta-RbMnHP3O10 was also isolated as a single phase and found to crystallize in the space group C2 (a = 12.2066(5) angstrom, b = 8.5243(3) angstrom, c = 8.8530(4) angstrom, beta = 107.233(2)degrees). Both structures consist of frameworks of corner-sharing MnO6 octahedra linked together by condensed phosphate anions, with Rb+ cations located in the intersecting channels. In both cases the Mn3+ octahedra exhibit unusual Jahn-Teller distortions indicative of a plasticity effect driven by the steric requirements of the condensed phosphate anions, and this causes a strong violet coloration similar to that observed in the manganese violet pigment; the structure of this has yet to be determined. Magnetic susceptibility measurements show that both RbMnP2O7 (T-N = 20 K) and beta-RbMnHP3O10 (T-N = 10 K) undergo a phase transition at low temperatures to an antiferromagnetically ordered state. Low-temperature neutron powder diffraction studies show that the magnetic ground states of each of these materials involve both ferromagnetic and antiferromagnetic super-superexchange interactions between orbitally ordered Mn3+, which are mediated by PO4 tetrahedra. These interactions are compared and discussed.

AB - Two previously uncharacterized members of the Rb-Mn-P-O system, RbMnP2O7 and beta-RbMnHP3O10, have been synthesized using a phosphoric acid flux synthetic route and their crystal and magnetic structures determined using neutron powder diffraction. The crystal structure of RbMnP2O7 (space group P2(1)/c, a = 7.3673(2) angstrom, b = 9.6783(2) angstrom, c = 8.6467(2) angstrom, and beta = 105.487(1)degrees) was found to be isostructural with RbFeP2O7. The polymorph beta-RbMnHP3O10 was also isolated as a single phase and found to crystallize in the space group C2 (a = 12.2066(5) angstrom, b = 8.5243(3) angstrom, c = 8.8530(4) angstrom, beta = 107.233(2)degrees). Both structures consist of frameworks of corner-sharing MnO6 octahedra linked together by condensed phosphate anions, with Rb+ cations located in the intersecting channels. In both cases the Mn3+ octahedra exhibit unusual Jahn-Teller distortions indicative of a plasticity effect driven by the steric requirements of the condensed phosphate anions, and this causes a strong violet coloration similar to that observed in the manganese violet pigment; the structure of this has yet to be determined. Magnetic susceptibility measurements show that both RbMnP2O7 (T-N = 20 K) and beta-RbMnHP3O10 (T-N = 10 K) undergo a phase transition at low temperatures to an antiferromagnetically ordered state. Low-temperature neutron powder diffraction studies show that the magnetic ground states of each of these materials involve both ferromagnetic and antiferromagnetic super-superexchange interactions between orbitally ordered Mn3+, which are mediated by PO4 tetrahedra. These interactions are compared and discussed.

KW - crystal structures

KW - phosphates

KW - refinement

KW - complexes

KW - cesium

U2 - 10.1021/ic901668u

DO - 10.1021/ic901668u

M3 - Article

VL - 49

SP - 934

EP - 942

JO - Inorganic Chemistry

T2 - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

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ER -