230种晶体学空间群的记号

230种晶体学空间群的记号

Symbols of the 230 Crystallographic Space Groups

空间群是点对称操作和平移对称操作的对称要素全部可能的组合。点群表示晶体外形上的对称关系，空间群表示晶体结构内部的原子及离子间的对称关系。空间群一共230个，它们分别属于32个点群。晶体结构的对称性不能超出230个空间群的范围，而其外形的对称性和宏观对称性则不能越出32个点群的范围。属于同一点群的各种晶体可以隶属于若干个空间群。

230种晶体学空间群的记号

Symbols of the 230 Crystallographic Space Groups

2P2m

c b n

m

2m

c2I

m 11m c R m R c m2

m c P

3m 333P3

3

Pm m Pn n Pm n Pn m Fm m Fm c Fd m Fd

c

Im m

m m

Ia d

1.The product was a mixture of unidentified dark blue microcrystals and brown

crystals　

2.The mixture was then heated at 180°C for four days in a Teflon-coated steel

autoclave. The product, consisting of clear single crystals of MAP-RHO1 and an unidentified white powder, was recovered by filtration and washed with deionized water.

3. Attempts to isolate this compound by removal of solvent (0 O C, l0-2mmHg)

resulted in decomposition to unidentifiable products.

4.Strong hydrogen bonding occurs only when the hydrogen atom is collinear with

the bonded atoms.

5. The hydrogen atom is located closer to one atom or the other.

6. Here the substitutional hydrogen atom located in a surface vacancy or the

hydrogen at an interstitial position of surface is a half-confined atom which is only weakly bound.

7. The ethylenediamine ligand was chosen for its ability to chelate copper ions

leaving two free positions translocated so that {Cu(en) 2 } 2+ can act as a linking agent between two POMs, via bridging oxygen atoms [4] and (c. We have studied the influence of the initial pH .

8.The ions or molecules surrounding the central atom are called ligands. Ligands

are generally bound to the central atom by a coordinate covalent bond (donating electrons from a lone electron pair into an empty metal orbital), and are said to be coordinated to the atom. There are also organic ligands such as alkenes whose pi bonds can coordinate to empty metal orbitals. An example is ethene in the complex known as Zeise's salt, K+[PtCl3(C2H4)]−.

9.One nickel ion is coordinated by three ligands (with low occupancy of a fourth ligand) and

the second is coordinated by five ligands.

10.The eleven tungsten centers of compound 1 have a distorted octahedral geometry.

11. All the tungsten atoms have distorted octahedral geometry and the bond-

valence sum (BVS) model25 clearly indicates that all the tungsten atoms are in the +6oxidation state.

12.(1) dispersion of the negative charge over many atoms of the polyanion and

13.Anal. Calc. For

14. which is not thought of as being novel.

15.be thought of as和be considered as 和be seen as作为“……被视为/被看作……"

的语义上讲，总体上3个表达一样, 类似还有：regard...as.../ view...as.../ treat...as.../