Marchettiite, (NH 4 )C 5 H 3 N 4 O 3 , a new organic mineral from Mount Cervandone, Devero Valley, Western–Central Alps, Italy

Abstract:

The new mineral marchettiite (IMA2017-066) is the natural equivalent of ammonium hydrogen urate. It has a simple molecular formula C5H7N5O3 and can be alternatively written as (NH4)C5H3N4O3. Marchettiite was found in a cleft at Mount Cervandone, Devero Valley, Piedmont, Italy, where it occurs as aggregates of opaque pale pink to white, platy prismatic crystals. This mineral has a white streak, dull and opaque lustre, it is not fluorescent and has a hardness of 2–2.5 (Mohs’ scale). The tenacity is brittle and crystals have a good cleavage parallel to {001}. The calculated density is 1.69 g/cm3. Marchettiite is biaxial (–) with 2V of 47.24°; the optical properties of marchettiite were determined by periodic-DFT methods providing the following values: α = 1.372, β = 1.681 and γ = 1.768. No twinning was observed. Electron microprobe analyses gave the following chemical formula: C4.99H6.97N4.91O3.00. Although the small crystal size did not allow refinement of structural data by single-crystal diffraction, we were able to refine the structure by powder micro X-ray diffraction. Marchettiite has space group P and the following unit-cell parameters: a = 3.6533(2) Å, b = 10.2046(7) Å, c = 10.5837(7) Å, α = 113.809(5)°, β = 91.313(8)°, γ = 92.44(1)° and V = 360.312 Å3. The strongest lines in the powder diffraction pattern [d in Å (I)(hkl)] are: 9.784(50)(001); 8.663(80)(01); 5.659(100)(011); 3.443(100)(10); 3.241(70)(003) and 3.158(100)(1. Marchettiite is named after Gianfranco Marchetti, the mineral collector who found this mineral.

SEEK ID: https://publications.h-its.org/publications/1576

DOI: 10.1180/mgm.2022.97

Research Groups: Computational Carbon Chemistry

Publication type: Journal

Journal: Mineralogical Magazine

Citation: MinMag 86(6):966-974

Date Published: 1st Dec 2022

Registered Mode: by DOI

Authors: Alessandro Guastoni, Fabrizio Nestola, Federico Zorzi, Arianna Lanza, Michelle Ernst, Paolo Gentile, Sergio Andò, Alessandra Lorenzetti

help Submitter
Citation
Guastoni, A., Nestola, F., Zorzi, F., Lanza, A., Ernst, M., Gentile, P., Andò, S., & Lorenzetti, A. (2022). Marchettiite, (NH4)C5H3N4O3, a new organic mineral from Mount Cervandone, Devero Valley, Western–Central Alps, Italy. In Mineralogical Magazine (Vol. 86, Issue 6, pp. 966–974). Mineralogical Society. https://doi.org/10.1180/mgm.2022.97
Activity

Views: 1868

Created: 3rd Feb 2023 at 15:33

Last updated: 5th Mar 2024 at 21:25

help Tags

This item has not yet been tagged.

help Attributions

None

Powered by
(v.1.14.2)
Copyright © 2008 - 2023 The University of Manchester and HITS gGmbH