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Free keywords:
rare earth compounds; crystal chemistry; superstructure
Abstract:
Single crystals of the indide Er-2.30(1) Ni-1.84(1) In-0.70(1) were
isolated from an arc-melted sample of the initial composition 5Er: 2Ni:
1In. Er2.30Ni1.84In0.70 crystallizes with a new superstructure of the
Mo2FeB2 type: P4/m, alpha = 738.6(2), c = 361.4(1) pm, wR2 0.0393, 487
F-2 values, 22 variables, BASF 0.500(3) ( meroedric twin matrix 010 100
00 (1) over bar). The structure may be described as an intergrowth
variant of slightly distorted AlB2 and CsCl related slabs. Formation of
the superstructure results in two crystallographically independent
sites 1a and 1c that center the CsCl slab. These sites have different
size and they are occupied by 90% In + 10% Er ( 1c) and 51% In + 49% Er
( 1a), respectively. The crystal chemical consequences are discussed on
the basis of a group-subgroup scheme.
