Huskic I., Novendra N., Lim D.-W. et al. · Chemical Science · 2019 · 4923-4929
Open a family to keep every result attached to its sample, method and conditions.
Paraphrased for this database from the authors’ stated interpretations — never quoted verbatim — and kept separate from reported measurements.
Synthetic stepanovite and zhemchuzhnikovite analogues are proton-conductive MOF minerals, with ZH reaching almost 3 x 10-3 S cm-1 at 25 deg C and 90% RH.
Caveat: ST2 could not be measured above 70% RH because of deliquescence.
4927 · Results and discussion · Fig. 4 · Linked to 3 structured results
ST1 and ST2 lose guest water upon mild heating to form crystalline dehydrated phases ST1d and ST2d while retaining the two-dimensional hcb framework layers.
4926 · Results and discussion · Fig. 2; Table 1 · Linked to 3 structured results
Substituting aluminium for iron in ZH gives a more exothermic formation enthalpy from oxides than the ST polymorphs, indicating enhanced thermodynamic stability.
4926 · Results and discussion · Table 2 · Linked to 3 structured results
Differences in conductivity between ST1, ST2 and ZH are tentatively linked to different hydrogen-bonded frameworks made by Mg(H2O)6(2+) ions and water guests.
Caveat: The authors describe this relationship as tentative.
4928 · Results and discussion · Fig. 4c-d; SI Fig. S1 · Linked to 3 structured results
Reduced conductivity after H/D exchange supports proton conduction rather than purely non-protonic ionic transport.
Caveat: The paper reports isotope-effect comparisons for ST1 and ZH, not ST2.
4928 · Results and discussion · SI Fig. S14-S15 · Linked to 4 structured results
Names and aliases are kept exactly within the paper’s own identity model.
| Material | Composition | Structure context | Source |
|---|---|---|---|
| Stepanovite polymorph ST1 | NaMgFe(C2O4)3.9H2ONa+, Fe3+ and hexaaquamagnesium Mg(H2O)6(2+) charge-balancing cations · Oxalate (C2O4(2-)) | 2D · PristineSynthetic stepanovite 1; ABCA'B'C' stacking of hcb sheets; R3c at 100 K. | 4925 · Results and discussion · Table 1; Fig. 1 |
| Dehydrated stepanovite ST1d | NaMgFe(C2O4)3.6H2ONa+, Fe3+ and Mg-aqua cations after guest-water loss · Oxalate (C2O4(2-)) | 2D · PristineDehydrated ST1 with partial corrugation of hcb layers; R3. | 4926 · Results and discussion · Table 1; Fig. 3 |
| Stepanovite polymorph ST2 | NaMgFe(C2O4)3.9H2ONa+, Fe3+ and hexaaquamagnesium Mg(H2O)6(2+) charge-balancing cations · Oxalate (C2O4(2-)) | 2D · PristineSynthetic stepanovite 2; ZH-like AB stacking of hcb sheets; P3c at 298 and 100 K. | 4926 · Results and discussion · Table 1; Fig. 1 |
| Dehydrated stepanovite ST2d | NaMgFe(C2O4)3.6H2ONa+, Fe3+ and Mg-aqua cations after guest-water loss · Oxalate (C2O4(2-)) | 2D · PristineDehydrated ST2 with corrugated hcb sheets preserving AB stacking; P3. | 4927 · Results and discussion · Fig. 3 |
| Zhemchuzhnikovite analogue ZH | NaMgFe0.4Al0.6(C2O4)3.9H2ONa+, mixed Fe3+/Al3+ nodes and hexaaquamagnesium Mg(H2O)6(2+) charge-balancing cations · Oxalate (C2O4(2-)) | 2D · PristineZH-like hcb layers stacked along an approximately 12.6 A crystallographic c-axis with guest-filled channels. | 4923 · Introduction |
Sample form, processing state and composition status define the context for measurements.
| Sample | Form and role | Processing and geometry | Source |
|---|---|---|---|
| ST1 crystalsresearch_0541__mat__mat_st1 | Single Crystal · Target Sample · Pristine Framework | Slowly evaporated large hexagonal plate-like crystals; hand-separated by morphology. | 4924 · Synthesis of ST1 and ST2 |
| Deuterated ST1research_0541__mat__mat_st1 | Pellet · Target Sample · Guest Loaded | Parent phase dehydrated then recrystallized from D2O in dry N2. | 4925 · Deuterated ST1 and ZH |
| ST1 compacted pelletresearch_0541__mat__mat_st1 | Pellet · Target Sample · Pristine Framework | Compacted powder pellet, 2.5 mm diameter, contacted with gold paste and 50 um gold wires.about 1.2 mm | 4925 · Alternative current (AC) impedance measurement |
| ST1d dehydrated single crystalresearch_0541__mat__mat_st1d | Single Crystal · Target Sample · Pristine Framework | ST1 single crystals gently heated at 50 deg C under vacuum for 12 h. | 4924 · Dehydration of ST1 and ST2 single crystals |
| ST2 crystalsresearch_0541__mat__mat_st2 | Single Crystal · Target Sample · Pristine Framework | Rapid evaporation/rotary evaporation product; elongated crystals with hexagonal cross-section. | 4924 · Synthesis of ST1 and ST2 |
| ST2 compacted pelletresearch_0541__mat__mat_st2 | Pellet · Target Sample · Pristine Framework | Compacted powder pellet, 2.5 mm diameter, contacted with gold paste and 50 um gold wires.about 1.2 mm | 4925 · Alternative current (AC) impedance measurement |
| ST2d dehydrated single crystalresearch_0541__mat__mat_st2d | Single Crystal · Target Sample · Pristine Framework | ST2 single crystals gently heated at 50 deg C under vacuum for 12 h. | 4924 · Dehydration of ST1 and ST2 single crystals |
| Bulk synthetic ZHresearch_0541__mat__mat_zh | Powder · Target Sample · Mixed Metal | Bulk sample obtained by milling Fe and Al oxalate precursors with water. | 4924 · Synthesis of ZH |
| Deuterated ZHresearch_0541__mat__mat_zh | Pellet · Target Sample · Guest Loaded | Parent phase dehydrated then recrystallized from D2O in dry N2. | 4925 · Deuterated ST1 and ZH |
| ZH compacted pelletresearch_0541__mat__mat_zh | Pellet · Target Sample · Mixed Metal | Compacted powder pellet, 2.5 mm diameter, contacted with gold paste and 50 um gold wires.about 1.2 mm | 4925 · Alternative current (AC) impedance measurement |