関連する実験動画
Updated: Jul 12, 2026

07:26
Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
まとめ
高濃度のサンディンは,高圧下では逆転的にトリクリニック段階に変化する鉱物です. この構造の変化は,圧力,温度,およびアルカリケーションの大きさによって制御され,高温変換に似ています.
科学分野:
- ミネラロジーと結晶学.
- 地化学とペトロロジー.
背景:
- 高サンディンは,アルカリフェルドスパート (K,Na) AlSi(3) O(8) の高温ポリモルフであり,さまざまな条件下で構造的変化を示す.
- モナルビトへの高温変換は,圧力誘発の相変化のアナログとして機能します.
研究 の 目的:
- 高圧下での高サニジンのトリクリニック段階への可逆変換を調査する.
- アルカリフェルドスパートにおけるこの相変化を制御する構造的制御を解明する.
主な方法:
- 様々な組成のアルカリフェルドスパートの高圧実験.
- 単元細胞の寸法と,移行点における構造的変化の分析.
主要な成果:
- 高圧のサニジンは,高圧でトリクリニック段階に逆転します.
- 異なった組成 (a ≈ 8.30 Å, b ≈ 12.97 Å, c ≈ 7.14 Å, β ≈ 116.2°) において,移行時の単位細胞の寸法は著しく似ています.
- テトラエドール角度を含む構造的変異は,アルカリケーションサイズ (Na+,K+) の変化に対応します.
結論:
- 高いサニジンからトリクリニックの相変換は,構造的に制御されています.
- 温度,圧力,Na/K比は,効果的なアルカリケーションのサイズと,フィールドスパート枠内でそれらの収納を変化させることで,構造的変動に影響します.
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