Bond-length distributions for ions bonded to oxygen: results for the lanthanides and actinides and discussion of the f-block contraction

Abstract

Bond-length distributions have been examined for 84 configurations of the lanthanide ions and 22 configurations of the actinide ions bonded to oxygen, for 1317 coordination polyhedra and 10 700 bond distances for the lanthanide ions, and 671 coordination polyhedra and 4754 bond distances for the actinide ions. A linear correlation between mean bond length and coordination number is observed for the trivalent lanthanides ions bonded to O 2À . The lanthanide contraction for the trivalent lanthanide ions bonded to O 2À is shown to vary as a function of coordination number, and to diminish in scale with an increasing coordination number. The decrease in mean bond length from La 3+ to Lu 3+ is 0.25 Å for coordination number (CN) 6 (9.8%), 0.22 Å for CN 7 (8.7%), 0.21 Å for CN 8 (8.0%), 0.21 Å for CN 9 (8.2%) and 0.18 Å for CN 10 (6.9%). The crystal chemistry of Np 5+ and Np 6+ is shown to be very similar to that of U 6+ when bonded to O 2À , but differs for Np 7+ . research papers 60 Olivier C. Gagné Bond-length distributions for ions bonded to oxygen Acta Cryst. (2018). B74, 49-62 Figure 10 Bond-length distributions for (a) [2+2+4]-coordination, (b) [2+6]coordination and (c) the aggregate of (a) and (b) for U 6+ O 8 polyhedra.

Mononuclear Hydroxo Carbonato Complexes of Np(V), Np(VI), and U(VI): A Density Functional Study

“…Pertinent structure parameters are collected in Table . Compared to Np(V) shorter bond lengths are expected for Np(VI) as its ionic radius is shorter by 3 pm, in line with results for other Np complexes . Np–O ax as well as the other Np–O bond lengths in Np(VI) complexes are on average shorter by 5 pm and 8–10 pm, respectively, than in analogous Np(V) species, Table and Table .…”

On the Crystal Chemistry of Inorganic Nitrides: Crystal-Chemical Parameters and Opportunities in the Exploration of Their Compositional Space

“…In this work, we use the method of Gagné & Hawthorne 59 to derive new bondvalence parameters for nitrides, provide a scale of Lewis acidity for nitrides, and further outline a baseline statistical knowledge of bond lengths for cations bonded to N 3-as a contribution to our gradual effort toward modernizing Shannon's set of ionic radii 60 (see refs. 50,[61][62][63][64] for bondlength statistics of cations bonded to O 2-; in prep for cations bonded to S 2-, Se 2-and/or Te 2-). Later in this work, we explore new and interesting venues for the exploratory synthesis of functional inorganic nitrides from a crystal-chemical perspective.…”

“…Gagné & Hawthorne state that deviations from such shape are the result of bond-topological, electronic and/or crystal-structure effects, 50 which they go on to describe for all cations of the periodic table observed bonding to O 2-in inorganic structures. 50,[61][62][63][64] Notable examples of anomalous bond-length distributions include a tri-modal distribution for [4] P 5+ -O 2bonds, 62 caused by varying bond-valence requirements as a function of the degree of polymerization of the [PO4] 3-oxyanion (i.e. bond-topological effects), a tri-modal distribution for [6] Mo 6+ -O 2-bonds, 50 arising from a combination of pseudo Jahn-Teller and bond-topological effects, and anomalously long tails at longer bond lengths for penta-coordinated ion configurations of Cr 2+ , Co 2+ and Cu 2+ , also caused by pseudo Jahn-Teller and bond-topological effects.…”

“…In light of the recent extensive review of the crystal chemistry of oxides and oxysalts by Gagné & Hawthorne,50,[61][62][63][64] we investigate our dataset of inorganic nitride structures for the occurrence of bond topological, electronic and/or crystal-structure effects, placing emphasis on the functional properties resulting from these effects. Compositional and structural divergences are expected between the compounds making up these two datasets.…”

On the Crystal Chemistry of Inorganic Nitrides: Crystal-Chemical Parameters, Bonding Behavior, and Opportunities in the Exploration of Their Compositional Space

“…In this work, we use the method of Gagné & Hawthorne 67 to derive new bondvalence parameters for nitrides, provide a scale of Lewis acidity for nitrides, and further outline a baseline statistical knowledge of bond lengths for cations bonded to N 3-; these data serve as a contribution to our gradual efforts of systematizing chemical bonding behavior in solids, toward modernizing Shannon's set of ionic radii 68 (see refs. 58,[69][70][71][72] for bond-length statistics of cations bonded to O 2-; in prep for cations bonded to S 2-, Se 2-and/or Te 2-), and are a useful aid to structure verification and the design of physically realistic crystal structures. In the second part of this work, we explore new venues for the exploratory synthesis of functional inorganic nitrides, using the systematic nature of this dataset to identify plausible ion configurations likely to lead to new and promising functional units to be transposed across various chemical spaces.…”