Topic
Beryllonite
About: Beryllonite is a research topic. Over the lifetime, 24 publications have been published within this topic receiving 182 citations.
Papers
TL;DR: In this article, some of the title compounds have been found to exhibit ferroelectricity at room temperature and their structure types can be classified in three series according to the cations coordination number (CN) and size.
Abstract: Some of the title compounds have been found to exhibit ferroelectricity at room temperature Their structure types can be classified in three series according to the cations coordination number (CN) and size: 1- single cation with CN 4: olivine and glaserite; 2- two cations with CN 4: Beryllonite and stuffed tridymite; 3- all cations with CN 4: α-LiZnPO4 is the unique case known
48 citations
1 Mar 1973
TL;DR: The refined lattice parameters of beryllonite are:a=8.178 (3) A,b=7.818 (2),c=14.114 (6), β=90.00° (2); space groupP21/n,Z=12.
Abstract: The refined lattice parameters of beryllonite are:a=8.178 (3) A,b=7.818 (2) A,c=14.114 (6) A, β=90.00° (2); space groupP21/n,Z=12. Integrated Weissenberg photographs were taken by using CuK α radiation and multiple film packs. The anisotropic refinement of the crystal structure by means of least-square methods gave a finalR value of 0.063 for the 1388 observed reflections. In the crystal structure PO4 and BeO4 tetrahedra, linked by shared oxygen atoms in a three-dimensional network, form pseudo-ditrigonal rings perpendicular to theb axis. The independent Na atoms lying in the channels formed by the rings are coordinated as an irregular “nine-cornered” polyhedron and as distorted octahedra.
23 citations
TL;DR: In this paper, the MGaSiO4, MAlGeO4 and MGaGeO 4 phases (M = Na, K) have been synthesized using flux, hydrothermal, and melt growth techniques and characterized by TEM and single crystal and powder X-ray diffraction.
19 citations
TL;DR: The phase relations in the (Na,K)AlGeO4 system have been investigated at atmospheric pressure over the temperature range 700-1100° C by X-ray powder diffraction and electron diffraction/microscopy as discussed by the authors.
Abstract: The phase relations in the (Na,K)AlGeO4 system have been investigated at atmospheric pressure over the temperature range 700–1100° C by X-ray powder diffraction and electron diffraction/microscopy. Four distinct structure-types occur in this system including the beryllonite, nepheline, kalsilite and KAlGeO4 types in order of increasing KAlGeO4 content. In contrast to the (Na,K)Al-SiO4 system, the nepheline structure is only stable over a narrow composition range around 25 percent K at temperatures above approximately 800° C and transforms reconstructively into the beryllonite structure at lower temperatures. The formation of domain microstructures in some K-rich phases has been directly observed by high-resolution electron microscopy and can be associated with the presence of diffuse scattering in their diffraction patterns. The structural trend observed across the (Na,K)AlGeO4 series as a function of composition can be rationalized to a large extent in terms of the dependence of the framework topology of these tridymite-derivative structures on the size of the alkali atoms.
15 citations
TL;DR: Vibrational spectroscopy served to determine the molecular structure of the mineral and the intense sharp Raman band at 1011 cm(-1), was assigned to the phosphate symmetric stretching mode.
12 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2012 | 1 |
| 2010 | 2 |
| 2005 | 1 |
| 2002 | 1 |
| 1993 | 5 |