13.2 The elemental substances of boron family 硼B metalloid 铝Al meta 镓Ga metal 铟In metal
13.2 The elemental substances of boron family metalloid metal metal metal
The elemental substances of boron (denote B) Allotropes(同素异形体):amorphous B-→brown powder (a few types)crystalline B->black-gray Properties:high chemical activity,high hardness high m.p and b.p a一菱形硼(B12)(one of the crystalline type of B): Atomic crystal 12 vertices,20 faces
The elemental substances of boron (denote B) Allotropes(同素异形体):amorphous B brown powder (a few types) crystalline B black-gray Properties: high chemical activity, high hardness high m.p and b.p α -菱形硼 (B12) (one of the crystalline type of B): Atomic crystal 12 vertices, 20 faces
13.3 The compounds of boron 1.Boron hydrides(borane) General formula of boranes:B Hn+4 and BHn+6 Example:B2H6 B4H10。。。。。o diborane borobutane H H No existence of BH B:2s22p1 H-BB-H The simplest borane:B2H HH The structure of B,H cannot be depicted as the right figure:
13.3 The compounds of boron 1. Boron hydrides (borane) General formula of boranes: BnHn+4 and BnHn+6 Example: B2H6 B4H10。。。。。。 diborane borobutane 。。。。 No existence of BH3 The simplest borane:B2H6 The structure of B2H6 cannot be depicted as the right figure: H H B B H H H H B:2s22p1
The structure of boranes B:one sp3 orbital from each boron overlaps a hydrogen's 1s orbital to give a three center bond to which two electrons are assigned(三中心两电子键).(B-H-B bridge) H H H Sp3 p denote: B B H SD 1s 要点:B的杂化方式, 三中心两电子键、氢桥
• The structure of boranes B: one sp3 orbital from each boron overlaps a hydrogen’s 1s orbital to give a three center bond to which two electrons are assigned (三中心两电子键). (B-H-B bridge) denote: H H B B H H H H 要点:B的杂化方式, 三中心两电子键、氢桥
The structure of BHio molecule B:sp3 hybridization Note:a B-B bond 119pm H 143pm 13 H H 110pm B (a)) (b)
The structure of B4H10 molecule 119pm 110pm 137pm 143pm 122。 171pm H B ( b ) B B B B H H H H H H H H H H H ( a ) B: sp3 hybridization Note: a B-B bond