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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Silicate garnets, general formula E 3 G 2 Si 3 O 12 , form an important class of rock-forming minerals and, in nature, most are solid solutions. Their crystal-chemical and solid-solution properties are sometimes interpreted in terms of the widely used Pyralspite-Ugrandite classification scheme, and this can lead to erroneous conclusions. In this study, published data are reviewed and analyzed to achieve a synthesis of relevant experimental and computational results and to construct a working “crystal-chemical model” for describing aluminosilicate garnet, E 3 Al 2 Si 3 O 12 , over different length scales. The pyrope-grossular (Py-Gr) solid solution is given special attention, because it has received a great deal of study. It also shows interesting crystal-chemical and thermodynamic mixing behavior. Computational and experimental investigations made on Py-Gr garnets indicate that the shorter Ca/Mg-O2 bond lengths appear to remain roughly constant in length across the binary and can be described as showing “Pauling limit-type” behavior. The longer Ca/Mg-O4 bonds behave differently, because they lengthen with increasing Gr component in the solid solution. Bond behavior in almandine-spessartine (Al-Sp) garnets appears to be partly different, because both Fe/Mn-O2 and Fe/ Mn-O4 bonds show “Pauling limit-type” behavior. E-O bond-length variations are continuous. The bonding type in all aluminosilicate garnet end-members is similar. An analysis shows that various computational simulations on Py-Gr solid solutions are consistent with each other with respect to E-O bond behavior and also with experimental IR, Raman, NMR spectroscopic, and X-ray diffraction results, but not completely with XAS studies made at the Ca edge. Ca/Mg-O4 bond behavior can be used to explain, partly, the nature of various micro/nanoscopic crystal-chemical and strain properties and macroscopic excess thermodynamic mixing behavior of Py-Gr garnets. Micro/nanostrain for the Py-Gr binary is asymmetric in nature, as are the various thermodynamic mixing functions ΔH ex , ΔS ex , and ΔV ex . The widely cited Pyralspite-Ugrandite classification scheme has limited use in terms of explaining many physical and chemical properties of garnet and it should not be used to predict or describe, for example, solid-solution behavior.

Silicate garnet: A micro to macroscopic (re)view