English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The crystal structure of the monoclinic form of ilvaite has been investigated. A crystal from Tsumo, Japan, was characterized by space group  P 2 1 / a , with  a  = 13.009(1) Å,  b  = 8.8008(3) Å,  c  = 5.8589(2) Å,  β  = 90.324(9)°, whereas a crystal from Techukhe, Siberia, had  P 2 1 / a ,  a  = 13.013(3) Å,  b  = 8.8197(6) Å,  c  = 5.8424(5) Å,  β  = 90.03(1)°. In the structure, the octahedra formed by oxygen atoms about Fe(11) and those about Fe(12) are alternately linked together, sharing edges to form a chain of octahedra parallel to  c . The monoclinic symmetry of ilvaite is characterized by ordering of Fe 2+  and Fe 3+  which are distributed over these two Fe sites with a ratio of 1:1. The atomic contents in the Fe(11) site, estimated from mean Fe(11) – O length, are:  Tsumo ilvaite  0.85 Fe 2+  and 0.15 Fe 3+ , and  Techukhe ilvaite  0.53 Fe 2+  and 0.47 Fe 3+ . From these atomic occupancies, the order parameter,  σ , of Tsumo ilvaite is calculated to be 75%, while that of Techukhe ilvaite 6%. From the two cases of monoclinic ilvaites, a relation between  β  and  σ  has been deduced; the result permits predicting  β  ≈ 90.45° for an ilvaite crystal having  σ  = 100%. The orthorhombic form of ilvaite may be defined as a form of ilvaite having  σ  = 0.

X-ray study on polymorphism of ilvaite, HCaFe 2 2+ Fe 3+ O 2 [Si 2 O 7 ]