... of molecular-orbital theory ( Burdett and Hawthorne 1993 ; Hawthorne 1994 , 1997 ). The variation of P-ϕ (ϕ: O 2− , OH − ) distances and ϕ-P-ϕ angles is of great interest for several reasons: mean bond-length and empirical cation and anion radii play an important role in systematizing chemical...

...+ vs. Si 4+ ). The variation of Be-φ (φ: O 2− , OH − ) distances and φ-Be-φ angles is of great interest for several reasons: mean bond-length and empirical cation and anion radii play a very important role in systematizing chemical and physical properties of crystals; variations...

... 2013 16 12 2013 We question the validity of two of the approved species, and thus we have not included them in our count. Bohseite, Ca 4 Be 3 AlSi 9 O 25 (OH) 3 , may not be distinct from bavenite, Ca 4 Be 2 Al 2 Si 9 O 26 (OH) 2 , given the results reported by Lussier and Hawthorne (2011...

... category additional to LCT and NYF ( Buck et al. 1999 ; Kjellman et al. 1999 ; Martin 1999 ; Černý 2000 ). An independent, but in many respects closely comparable classification was offered recently by Zagorskyi et al. (1999) . “Glucine” , allegedly CaBe 4 (PO 4 ) 2 (OH) 4 ·0.5H 2 O...

... ). APPENDIX 1. LIST OF VALID AND POTENTIALLY VALID MINERAL SPECIES (IN QUOTATION MARKS) CONTAINING ESSENTIAL BERYLLIUM M ineral, crystal system and formula E nvironment L ocalities R eferences Aminoffite (see note)
 Tetragonal
 Ca 3 Be 2 Si 3 O 10 (OH) 2 Veins and cavities...

... 3.8×3.8***     FD: 14.6 Chiavennite p 47     CaMn[Be 2 Si 5 O 13 (OH) 2 ]·2H 2 O      Pnab      a = 8.729, b = 31.33, c = 4.903     -CHI: [001] 9 3.9×4.3*     FD: 20.9 Clinoptilolite p 40     (Na,K) 6 [Al 6 Si 30 O 72 ]·20H 2 O      C 2/ m      a = 17.7...