March 3, 2026

Model of the Crystal Structure of Sodium-Depleted Sacrofanite. Problem of the Sacrofanite Identification

Key Points

The crystal structure model reveals the unique properties of sodium-depleted sacrofanite, including its hexagonal arrangement and lattice parameters.
Lattice parameters measured were a = 12.90519 Å and c = 74.2181 Å, contributing to understanding of minerals in the cancrinite group.
Analysis using infrared spectroscopy confirmed the presence of zeolitic cavities in sacrofanite, differing from its holotype counterpart.
This identification may enable further studies into the geological significance of sodium-depleted variants in various minerals.

Abstract

A structural model of the sodium-depleted analogue of sacrofanite, a 28-layer cancrinite-group mineral with the empirical formula (Na3.18Ca2.81K1.93)(Si6.10Al5.83Fe0.07O24)(SO4)1.95F0.51Cl0.19(OH)0.23⋅ 0.155H2O from sanidine syenite of the Sacrofano paleovolcano, Latium (Italy) has been built. The investigated mineral is hexagonal, sp. gr. P-62c, with the lattice parameters a = 12.90519(13), c = 74.2181(10) Å, V = 10704.6(3) Å3 close to those of holotype sacrofanite. The aluminosilicate framework of the investigated sodium-depleted sacrofanite contains columns of zeolitic cavities of four types: cancrinite, sodalite, Losod, and liottite. Their presence is confirmed by the IR spectroscopy data, unlike holotype sacrofanite, the published IR spectrum of which contains no characteristic band of the liottite cage at 547 ± 4 cm–1.

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Model of the Crystal Structure of Sodium-Depleted Sacrofanite. Problem of the Sacrofanite Identification

Key Points

Abstract

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