The scientific literature in chemistry and physics abounds with abbreviations of chemical compounds, physical methods and mathematical procedures. Unfortunately, many authors take it for granted that the reader knows the meaning of an abbreviation, something quite trivial for a specialist. For the less informed reader, these abbreviations thus present definite communication problems. The Gmelin Institute of Inorganic Chemistry of the Max Planck Society has collected more than 4000 abbreviations for methods and terms from chemistry, physics and mathematics and more than 4000 chemical compounds (mostly ligands in coordination chemistry and standard reagents for physical and analytical methods). GABCOM and GABMET provide an overview enabling readers and authors to check the definition of an abbreviation used by an author and to see whether this abbreviation is already being used for other purposes. GABCOM and GABMET are also in preparation in electronic form (data file and search software) for IBM-PC or compatible computers.

"Organoiron Compounds" A, Ferrocene 10 systematicalty covers the literature through the end of 1986 and includes so me references published more recently. A formula index provides ready access to the compounds covered. This volume ends the description of mononuclear unbridged disubstituted ferrocenes, 1 2 FeC HRR . The description of the unbridged disubstituted ferrocenes was initiated with lO a 1 2 "Organoiron Compounds" A, Ferrocene 7 (starting with R and R containing C and Hand 1 containing halogen at least in R\ and continuing with compounds containing 0 at least in R to form alcohols and phenols, their esters, ethers, acetals, and aldehydes), and was foltowed 1 by "Organoiron Compounds" A, Ferrocene 8 (with at least R containing 0). "Organoiron 1 Compounds" A, Ferrocene 9 treated compounds in wh ich at least R contains N, S, Se, B, or Si. This volume now comprises the rest of the disubstituted ferrocenes containing P, As, or a 1 metal at least in R . Beyond that it includes the description of alt the mononuclear unbridged trisubstituted ferrocenes, FeClOH7R1R2R3. Series A so far comprises volumes A 1 to A 10 and has been surveyed in the preface to A 7 (1980). The data in tables are given in abbreviated form without dimensions; for dimensions, explanations, and further abbreviations used, see p. X (next page). Additional remarks are given in the headings of the tables where necessary.

A broad coverage of boron topics is provided. Structural elucidations and convenient routes to useful hydroboration reagents are presented as well as boron compounds used for medical purposes. Special attention is devoted to theoretical studies and calculations on small boron-hydrogen and boron-noble gas species including molecules like BH, which are rather favorite subjects of theoreticians for testing various methods of calculation.

The present issue, Volume 2 of "Boron Compounds" 4th Supplement of the Gmelin Hand book, updates the previous issues by reporting the literature on boron-oxygen systems published up to 1988. For some important recent developments literature is covered through mid-1992; this concerns, for example, the compounds -Ba3 B306h and U B305J which became of interest as materials with nonlinear optical properties. The volume directly com plements the earlier "Boron Compounds" 3rd Supplement Volume 2. In the original literature, alternative formulations are frequently used for the same com pound. This is especially true for many borates. Often, these species are neither completely heteropolar nor covalent, and an experimentally based decision has not been made. Hence, the use of brackets does not necessarily reflect a truly salt-like character. Volume 1 (systems with hydrogen and noble gases) of this particular supplement will be published subsequently, whereas Volume 3a (boron and nitrogen), Volume 3b (boron and nitrogen, boron and fluorine), and Volume 4 (boron compounds containing Cl, Br, I, S, Se, and Te, as well as a section containing carboranes) have already been published. All volumes of the 4th supplement will be augmented by a formula index. The IUPAC nomenclature is generally adhered to; thf means tetrahydrofuran; and occa sionally additional abbreviations for compounds are explained in the text. Positive signs for chemical shifts of the NMR signals indicates downfield shifts from the references, usually internal (CH3)4Si for olH and 013C with others being specified."

PF3, (CH3)3SiCl -> (CH3)3SiF, and RC(O)Cl -> RC(O)F. Others include the conversion of (C6H5)3P into (C6H5)3PF2 and of (R3NC(S)S)2 into R2NCF3, R=alkyl. In organic chemistry, fluorides are easily accessible from alcohols, geminal fluorides RR'CF2 from the respective aldehydes or ketones, and acyl fluorides RC(O)F from carboxylic acides by using DAST. Because DAST is easy to handle and gives clean reactions in syntheses, this Gmelin volume devotes much space to the description of the chemical and physical properties od DAST.

The present volume in the organogermanium series describes mononuclear compounds containing only germanium-carbon and germanium-hydrogen bonds (Chapter 1.3). Germanium hydrides with other additional non-carbon ligands, such as halogen or oxygen bonded groups, appear in later chapters according to the Gmelin principle of the last posi tion. Compounds with Ge-H and Ge-O bonds have already been described in Volume 5, Section 1.5.1.4, pp. 50/62. The present volume covers the literature to the end of 1992 and includes many references up to 1994. The nomenclature recommended by IUPAC has been generally adhered to. However, compound names were largely avoided, as most of the compounds are presented in tables and are only identified by their formulas. Many of the data in the tables appear in abbreviated form without units; general explanations are given on pp. X/XI. The volume contains an empirical formula index (p. 327) and a ligand formula index (p.341). The editor wishes to express his gratitude to the former author, Professor J. E. Drake, and to Professor J. Satge for his kind advice and fruitful collaboration. Thanks are due also to Dr. A. R. Pebler for editing the English text and to Mr. H.-G. Karrenberg for drawing the numerous formulas and molecular structures.

In der chemischen und physikalischen Fachliteratur werden hAufig AbkA1/4rzungen fA1/4r chemische Verbindungen sowie fA1/4r Arbeitsmethoden, mathematische Rechenverfahren u.a. verwendet. Leider ist es eine verbreitete Arbeitsweise, daA die Autoren als Spezialisten die fA1/4r sie triviale Kenntnis dieser AbkA1/4rzungen voraussetzen. FA1/4r den nicht spezialisierten Leser bereiten diese AbkA1/4rzungen daher gewisse VerstAndnisprobleme. Das Gmelin-Institut fA1/4r Anorganische Chemie der Max-Planck-Gesellschaft hat aus der Literatur des Zeitraums 1950-1990 eine Sammlung solcher AbkA1/4rzungen erarbeitet. Im vorliegenden Buch sind mehr als 4000 AbkA1/4rzungen fA1/4r Methoden und Begriffe aus Chemie, Physik und Mathematik und A1/4ber 4000 AbkA1/4rzungen fA1/4r chemische Verbindungen (insbesondere Komplexbildner und Standard-Substanzen physikalischer MeAmethoden) zusammengestellt. Mit GABCOM und GABMET kAnnen Leser und Autoren feststellen, was mit einer speziellen AbkA1/4rzung gemeint ist, bzw. ob die von ihnen gewAhlte AbkA1/4rzung nicht schon fA1/4r andere Verfahren oder Verbindungen benutzt wird. GABCOM und GABMET sind auch in elektronisch lesbarer Form (Daten und SuchoberflAche) fA1/4r IBM-PCs oder kompatible Rechner in Vorbereitung.