temperatures down to 4.2 K (5 000–25 000 cm–1). From the spectrum of cadmium voltaite, iron(III) ligand-field transitions are found at 14 000 (6A1g→4T1g), 19 000 (6A1g→4T2g), and 23 500 cm–1(6A1g→4A1g,4Eg). In the mixed-valence crystals a broad absorption band centred at 16 500 cm–1 is the intervalence charge-transfer transition. Its half-width and integrated band area vary only slightly from room temperature
火山灰,K 2 Fe II 5 Fe III 3 Al [SO 4 ] 12 ·18H 2 O晶体和固溶体K 2 Fe II x Cd II 5– x Fe III 3 Al [SO 4 ] l2 ·18H 2 O,已经通过
化学分析和X射线衍射制备并表征。固溶体是同构的[ O h 8(Fd 3 c)],仅与27.25(x= 5)至27.49Å(x = 0)。漫反射光谱被记录在室温(5 000-50000厘米-1)和单晶透射光谱在温度下降到4.2 K(5 000-25000厘米-1)。从
镉镉的光谱中,发现
铁(III)
配体场跃迁为14 000(6 A 1 g → 4 T 1 g),19 000(6 A 1 g → 4 T 2 g)和23 500 cm –1(6 A 1 g → 4 A 1g, 4 E g)。在混合价晶体中,以16 500 cm –1为中心的宽吸收带是间隔电荷转移跃迁。从室温到4