Assignment of 23Na MAS NMR signals of ammonium- and lanthanum-exchanged sodium Y zeolites

Hermann K. Beyer, Borbély G. Páł, Hellmut G. Karge

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Two distinct 23Na MAS NMR lines in spectra of hydrated Na,NH4-Y zeolites at about -9 and -13 ppm (referenced to crystalline NaCl) were assigned to sodium lattice cations located in the large cavities (SIII) and inside the truncated octahedra (SI′ or SII′). This assignment was supported by the appearance of these two signals in spectra of air-dried and heat-treated La,Na-Y zeolites (obtained by conventional or contact-induced solid-state ion exchange), the more so as the intensity ratios corresponded to the cation distribution known to arise after the distinctly different pretreatments. It is concluded that slowly tumbling sodium cations are located in SIII whereas Na cations in truncated octahedra show stronger quadrupole interactions. A 23Na signal at -5.5 ppm sometimes observed in spectra of La,Na-Y zeolites was tentatively assigned to sodium cations located in the hexagonal prisms (SI).

Original languageEnglish
Pages (from-to)67-71
Number of pages5
JournalMicroporous Materials
Volume1
Issue number1
DOIs
Publication statusPublished - 1993

Fingerprint

Zeolites
Lanthanum
Ammonium Compounds
lanthanum
zeolites
Cations
Positive ions
Sodium
Nuclear magnetic resonance
sodium
cations
nuclear magnetic resonance
International System of Units
Barreling
Prisms
Crystal lattices
pretreatment
prisms
Ion exchange
quadrupoles

Keywords

  • Na MAS NMR signal assignment
  • contact-induced solid-state ion exchange
  • La,Na-Y zeolites
  • lattice cation distribution

ASJC Scopus subject areas

  • Chemistry(all)
  • Engineering(all)
  • Materials Science(all)

Cite this

Assignment of 23Na MAS NMR signals of ammonium- and lanthanum-exchanged sodium Y zeolites. / Beyer, Hermann K.; Páł, Borbély G.; Karge, Hellmut G.

In: Microporous Materials, Vol. 1, No. 1, 1993, p. 67-71.

Research output: Contribution to journalArticle

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T1 - Assignment of 23Na MAS NMR signals of ammonium- and lanthanum-exchanged sodium Y zeolites

AU - Beyer, Hermann K.

AU - Páł, Borbély G.

AU - Karge, Hellmut G.

PY - 1993

Y1 - 1993

N2 - Two distinct 23Na MAS NMR lines in spectra of hydrated Na,NH4-Y zeolites at about -9 and -13 ppm (referenced to crystalline NaCl) were assigned to sodium lattice cations located in the large cavities (SIII) and inside the truncated octahedra (SI′ or SII′). This assignment was supported by the appearance of these two signals in spectra of air-dried and heat-treated La,Na-Y zeolites (obtained by conventional or contact-induced solid-state ion exchange), the more so as the intensity ratios corresponded to the cation distribution known to arise after the distinctly different pretreatments. It is concluded that slowly tumbling sodium cations are located in SIII whereas Na cations in truncated octahedra show stronger quadrupole interactions. A 23Na signal at -5.5 ppm sometimes observed in spectra of La,Na-Y zeolites was tentatively assigned to sodium cations located in the hexagonal prisms (SI).

AB - Two distinct 23Na MAS NMR lines in spectra of hydrated Na,NH4-Y zeolites at about -9 and -13 ppm (referenced to crystalline NaCl) were assigned to sodium lattice cations located in the large cavities (SIII) and inside the truncated octahedra (SI′ or SII′). This assignment was supported by the appearance of these two signals in spectra of air-dried and heat-treated La,Na-Y zeolites (obtained by conventional or contact-induced solid-state ion exchange), the more so as the intensity ratios corresponded to the cation distribution known to arise after the distinctly different pretreatments. It is concluded that slowly tumbling sodium cations are located in SIII whereas Na cations in truncated octahedra show stronger quadrupole interactions. A 23Na signal at -5.5 ppm sometimes observed in spectra of La,Na-Y zeolites was tentatively assigned to sodium cations located in the hexagonal prisms (SI).

KW - Na MAS NMR signal assignment

KW - contact-induced solid-state ion exchange

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KW - lattice cation distribution

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