The crystal structure of K_0.54(Mn,Fe)F₃ at room temperature

Abstract

A specimen of flux-grown K0.54(Mn,Fe)F 3 was studied at room temperature by single-crystal X-ray diffractometry. The crystal has a structure of the tetragonal tungsten-bronze type with a doubled c axis.

Magnetic properties of linear trimers in fluoride analogs of tetragonal tungsten bronze

“…Neither of the distortions, however, lowered the space group symmetry. The ratio C u M /C M $ 0.60 supports the conclusions that ionic ordering is the same as that reported for K 0.54 Mn 0.54 Fe 0.46 F 3 [2], and that linear trimers were formed [3,4]. After making corrections for uncoupled paramagnetic ions and non-zero y 0 , a fit of w M (calculated) with w M (observed) was obtained for each of the five compounds from the respective equations derived from the recipe by Mabbs and Machin [7].…”

“…1a), tungsten ions occupy all 8j and 2c sites. K 0.54 Mn 0.54 Fe 0.46 F 3 , a fluoride analog of TTB reported by Banks et al [2], belongs to space group C 8 4v -P4 2 bc. In this structure, variations in M-F distances show that Mn 2 + ions occupy one set of 8c sites, and Fe 3 + ions occupy a second set of 8c sites; this ordering of Mn 2 + and Fe 3 + ions doubles the c dimension of the unit cell.…”

Zur Kristallstruktur von LiPdGaF6, RbPdAlF6 und K1,06Pd0,95Fe1,05F6

“…K,,,,Pdo,,,Fe,,o,F, kristallisiert rnit a = 1279,07 (7), c = 800,2(1)pm isotyp zu K,,,,MnFeF, (a = 1276,5(1), c = 800,2(1)pm, [3]). In K,,,Pd,,,,Fe,,,,F, sind Fe3+ und Pd2' annahernd regular oktaedrisch von Fluor umgeben, die mittleren Zentralteilchen-Ligand-Abstande unterscheiden sich dabei rnit aF:' -F = 191,6pm und dp:'pF = 215,9pm merk- (2)z+/Fe(l)z+'3+)] = 64,9; r[Fe(2)3+] = 58,5 pm.…”

Structural transition in KMnCrF6 – a chemically ordered magnetic ferroelectric

“…9 Even though its ferroelectricity has not been directly measured, it adopts a polar structure typical of ferroelectric TTB bronzes, and it orders magnetically at low temperature. 10,11 KMnFeF 6 crystallizes in the acentric tetragonal space group P4 2 bc. 10 The unit cell parameters show a doubling of the c-axis with respect to the fundamental TTB cell (a E 12 Å, c E 2Ác TTB E 8 Å).…”