Bond-length distributions for ions bonded to oxygen: Metalloids and post-transition metals

Abstract

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.

Brandãoite, [BeAl2(PO4)2(OH)2(H2O)4](H2O), a new Be–Al phosphate mineral from the João Firmino mine, Pomarolli farm region, Divino das Laranjeiras County, Minas Gerais State, Brazil: description and crystal structure

“…The refined site-scattering values are equivalent to 15 electrons per site, consistent with full occupancy by P 5+ . There are two Al sites octahedrally coordinated by six anions with < Al –Ф> distances of 1.897 and 1.899 Å, close to the value of 1.903 Å given by Gagné and Hawthorne (2017 b ) for ordered minerals and inorganic compounds. The refined site-scattering values are equivalent to 13 electrons per site, consistent with full occupancy by Al 3+ .…”

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

“…Such propositions are in-line with the results of the bond-length dispersion analysis of Gagné & Hawthorne for non-metals 62 and metalloids/post-transition metals. 63 With the 2p states of N being slightly more energetic than those of O (due to its lower electronegativity), we presume that LP stereoactivity may be possible for cations with higher-energy states such as In + /Ge 2+ , is most likely for elements Sn 2+ , Pb 2+ , As 3+ , Sb 3+ and Se 4+ , and is least favorable for late-period, higher group elements.…”

“…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.…”